Abstract: 【Objective】 In order to investigate the effects of compound sodium dinitrophenol (CSN), plant polysaccharides (DSK), succinyl (D2), and compound nanooxygen (FN-6) on the stress resistance of cotton plants, the optimal combination ratio is going to be sought. 【Methods】 This study used a quadratic universal rotation combination design to determine the content of plant peroxidase (POD), catalase (CAT), superoxide dismutase (SDO), malondialdehyde (MDA), and indoleacetic acid (IAA). Design Expert 13 was used to establish a functional model for it. F-test was used to analyze the significance of each regression model and regression coefficient. Afterwards, the model would be used to analyze the effect of PGR application on plant enzyme activity and endogenous IAA content and entropy weight method was used to select plant POD activity as a representative indicator to simulate and screen the optimal combination plan for its regression model. Then the optimal application ratio was obtained. At the same time, the optimization results of representative indicators were verified through four comprehensive evaluation methods: TOPSIS method (Ci), entropy method (Si), factor analysis (ε j), and rank sum ratio comprehensive evaluation method (RSR). The consistent results showed that the best application effect was achieved at the zero level, and the application amount could affect plant enzyme activity and endogenous IAA content. 【Results】 With the increase of PGR application, the activities of POD, SOD, CAT and endogenous IAA in plants showed a trend of first increasing and then decreasing, while the MDA content showed a trend of first decreasing and then increasing. The impact of various factors on plant POD activity was as follows: DSK>FN-6>CSN>D2, the impact on plant CAT was as follows: FN-6>CSN>DSK>D2, and the impact on plant SOD, MDA, and endogenous IAA content was as follows: CSN>DSK>FN-6>D2. 【Conclusion】 Through experimental simulation, the optimal application plan is CSN: 446.04-448.73 mg/hm² FN-6:526.28-528.96 mg/hm², DSK:526.28-528.96 mg/hm², D2:446.04-448.73 mg/hm².