Abstract: 【Objective】 By analyzing the change of sweat form during training and sweat index after 2,000 m test of 6 young Yili horse stallion undergoing conditioning training, the influence of conditioning training on the sweat form and sweat index of Yili horse was explored, and the experience of folk horse domestication was theorized. It provides theoretical basis and data support for the establishment of scientific training system and the monitoring of athletic performance of Yili horses. 【Methods】 Six two-year-old Yili horse stallions with consistent management and untrained training were selected from Zhaosu Stud Farm in Yili, Xinjiang. The training was conducted and sweat morphological changes were observed. Test races were organized on the second day after the appearance of mud sweat (MS), foam sweat (FS) and water sweat (CS), and sweat samples were collected immediately after the race. Heart rate (HR) and respiratory rate (RR) were monitored and the results were analyzed. Lactic acid (LA), sodium ion (Na⁺), potassium ion (K⁺), magnesium ion (Mg²⁺) and other 14 sweat indexes were detected in the sweat samples. 【Results】 After the 10-week conditioning training of 2-year-old Yili horses, the changes of sweat morphology and 2000 m test race results were obvious, and the change trend of sweat LA in the three sweat morphology stages was obvious. Immediately after the race, the content of LA in sweat decreased with the change of sweat morphology, and the content of LA in sweat in CS stage was significantly lower than that in MS stage (P <0.05). The content of Na+ in sweat after CS stage was significantly lower than that in MS stage (P <0.05). The content of K⁺ in sweat after training was significantly higher in CS stage than in MS stage (P <0.05). The content of Ca²⁺ in sweat after CS stage was significantly higher than that during MS stage (P <0.05). Cl- content reached the highest value after MS stage, and the difference was significant between MS stage and CS stage (P <0.05). The levels of Mg²⁺ and Cu²⁺ in sweat of Yili horses decreased with the change of sweat morphology after the test, and Mg²⁺ and Cu²⁺ were significantly lower in CS stage than in MS stage. 【Conclusion】 With the progress of conditioning training program, the sweat morphology and sweat index of Yili horses changed, and different sweat morphology revealed the different training degree and movement performance of individuals, among which the detected sweat LA and ion indexes may be the indicators to evaluate the training level and training stage of Yili horses during training.