ABSTRACT Introduction: Due to the lower atmospheric density at high altitudes, the spherical surface of the table tennis ball offers less resistance, requiring higher performance from its players. The athletes' reaction time and movement speed can improve significantly. Objective: This paper studies the changes in the fitness level of Chinese table tennis players under training at high altitudes. These results can serve as a reference to formulate and implement the training strategy of the Chinese table tennis team. Methods: The performance of 12 outstanding table tennis players in the competition was explored. After arriving at the high altitude, the athletes practiced training for four weeks. The athletes' biochemical parameters and heart rates were evaluated before and after training. These data were statistically treated. Results: The heart rate of the athletes in the third week after the experiment was lower than before, with no significant difference (P>0.05). The hematocrit value of table tennis players in training showed a temporary elevation after one week, significantly different from that before the experiment (P<0.05). After two weeks of exercise at a high altitude, the hematocrit value of the athletes remained at a high level (P<0.05). Conclusion: Table tennis players can improve their physical conditions with training at high altitudes, including aerobic and anaerobic properties. High-intensity exercise at high altitudes is also beneficial for improving athletes' strength, speed, and reaction time quality. Level of evidence II; Therapeutic studies - investigating treatment outcomes.