Taking 5 years old apple varieties Micui and Qincui as experimental materials, 29% lime-sulfur agent, Guodanmei and carbaryl were selected to carry out flower and fruit thinning experiments, and the thinning effects of different chemical agents were studied in order to provide reference for chemical flower and fruit thinning of apples in Ili River Valley. The results showed that the three chemical agents had different degrees of flower and fruit thinning effect on honey crisp and Qincui apple varieties. From the comprehensive comparison of single fruit ratio, fruit setting rate and empty fruit rate, 29% lime sulfur mixture water agent 1.0°Bé and fruit Danmei 150 times had better effect on Qincui flower thinning, 29% lime sulfur mixture water agent 0.75°Bé and fruit Danmei 200 times had better effect on honey crisp flower thinning, and carbaryl 400 times had better effect on Qincui and honey crisp apple fruit thinning. The treatment of chemical flower and fruit thinning agent had a certain effect on improving the quality indexes of some fruits of Qincui and Micui apples, which was mainly reflected in the increase of single fruit weight, soluble solids and calcium content. The use of chemical flower and fruit thinning technology can save labor by 65.83%, reduce costs by 482.5-542.5 yuan/667 m², and save costs and increase efficiency significantly.