Abstract: 【Objective】 This experiment conducted aims to investigate the effect of chemical topping on cotton boll formation and photosynthetic characteristics by using indirubicin compounded with different accelerators in the hope of providing some scientific and theoretical basis for the research application of indirubicin compounded with accelerators on cotton boll regulation and photosynthetic characteristics. 【Methods】 The experiment was conducted in Shaya County, Aksu Region, Xinjiang, China, from April to October 2022.The cotton variety under test was Xinluzhong 84, and the test chemicals were mainly indurated with thiram and auxin, compounded with thiram(0.1%, T₁), sodium compounded phenol(98% of the original drug, T₂), aminoxate(8% of the preparation, T₃), 14-hydroxy brassin(0.01%, T₄)and naphthalene acetic acid(98% of the original drug, T₅), with conventional micronutrient capping as the control(CK), a total of six treatments were used to investigate the effects of micronutrient complex promoters on the spatial and temporal distribution and photosynthetic characteristics of cotton boll. 【Results】 The maximum accumulation rate of dry matter was reached at about 20~30 d after the treatment, and the net photosynthetic rate reached its maximum at about 20 d after the treatment, so it could be inferred that cotton entered the critical period of reproductive growth at about 20~30 d after the treatment, and all the compound treatments could improve the sitting rate, net photosynthetic rate and dry matter accumulation rate of the upper middle and lower inner peripheral boll. 【Conclusion】 The rapid accumulation period of T₅ treatment was prolonged by about 5 d compared with CK, and the sitting rate of inner and lower outer boll of cotton plant was significantly different from that of CK.The sitting rate of inner and lower outer boll increased by 15.00% and 20.00% respectively, and that of middle inner and outer boll increased by 24.00% and 25.00% respectively, and the number of cotyledons increased by 1.13, and the number of boll set per plant increased significantly by 0.84.Therefore, it is recommended to use T₅ combination type chemical topping agent for cotton chemical topping.