Biological regulators as a new preparations can promote the natural biological metabolism of crops, enhance the nutrients absorption and utilization, increase the abiotic stress resistance of crops and improve the quality and yield, which is commercially used extensively because of its less dosage and obvious effects. Nevertheless, a large number of biological modulators are flooded with different types, brands and dosage forms in market, interfered seriously with users’ choices and its real effect was difficult to assess. To explore the influence of different biological regulator on fruit quality. Taking the “crystal pomelo” of 5 years old as the research object, a field trial was carried in pomelo science and technology demonstration park, nongdao town, ruili city, in Yunnan province with 97°42° east longitude and 23°52°north latitude. The research area was 0.15 hm2, the plant spacing was 3 m×5 m, and the planting density is 660 plant/hm2. During the whole growth stage, two times of foliar spraying were applied to each treatment include the beginning of the swelling (May 14, 2019) and bentonite fruiting (June 28, 2019). Four kinds of plant growth regulators (0.1% Clopidourea 100 times: T1; 20% Gibberellic acid 2000 times: T2; 0.015% Brassinolide 2000 times: T3; 99% α-Sodium naphthalene acetate: T4) and three kinds of bio-stimulants (Seaweed essence 800 times: T5; Algal polysaccharides 800 times: T6. Alginic acid 800 times: T7) with water as the control (CK) were foliar sprayed in pomelo growth stage. When the pomelo was maturity (Sep 20, 2019), 5 pomelos were picked from the different growing parts of the tree canopy, middle, lower, inner and outer. Pomelos were picked in each plot, mixed, and then divided according to the method of quartering, 10 fruits were selected as one fruit sample for each repeat. Testing, comparative and analysis 12 kinds of conventional fruit quality indexes (Moisture content, Total soluble solids, Titratable acid, Solid acid ratio, Vitamin C, Sucrose, Glucose Citric, Malate, Pectin, Cellulose and Lignin) and 9 kinds of mineral elements content (N, P, K, Ca, Mg, Fe, Cu, Zn and Ni) under different treatments. The principal factor analysis, cluster analysis and aggregated boosted tree analysis method were used to comprehensive evaluation fruit quality. The results showed that leaf spraying plant growth regulator promoted the soluble solid and titratable acid content significantly. The soluble solids content of pomelo fruits under different treatments ranged from 8.2 to 9.9%. Compared with CK treatment, T1, T2, T3, T4 and T7 treatment significantly increased the soluble solids of grapefruit by 13.1%, 11.9%, 17.9%, 15.5% and 16.7%, respectively. The titratable acid content of pomelo under different treatments ranged from 0.45 to 0.56%. T1, T2, T3, T4, T5 and T6 treatment increased by 17.8%, 13.3%, 24.4%, 11.1%, 15.6% and 22.2% compared with CK treatment. Plant growth regulation and bio-stimulant were significantly increased pomelo fruit glucose content and lignin content, and reduced the content of pectin and cellulose. Compared with CK treatment, T1, T2, T3, T4, T5, T6 and T7 treatments increased glucose content by 29.9%, 155.9%, 140.2%, 99.2%, 43.8%, 46.9% and 61.7%, the contents of pectin in T1, T2, T3, T4, T5, T6 and T7 were significantly reduced by 31.3%, 42.1%, 27.8%, 42.1%, 38.3%, 33.0% and 41.0%, pomelo lignin increased significantly by 215.8%, 182.9%, 156.6%, 332.2%, 196.7%, 119.1% and 263.8%, respectively. As a whole, bio-stimulant facilitated the content of trace elements, but plant growth regulator had no obvious effect on it, both no significantly effect on pomelo NPK nutrient content. Comprehensive analysis found that T3 treatment had an overall best fruit quality, as had the biggest comprehensive score, and cluster analysis also divided T3 treatment into the first group, which showed that its sucrose, malate, and lignin content was the lowest, but soluble solid, solid acid, sucrose, glucose and citric was the highest, the synthesis score was 1.57. Aggregated boosted tree analysis method was used to analysis the relative contribution of fruit quality factors on soluble solids under different groups, further confirmed that the glucose, sucrose and lignin were the top three contributors of different groups under foliar spraying treatment, and primary factors which effect pomelo soluble solids was glucose, sucrose and lignin in turn, the relative contribution rate was 40.2%, 36.0% and 27.2% respectively.