Objective: The purpose of this study is to investigate associations among ratings of perceived exertion (RPE), heart rate (HR) and blood lactate levels (Bla) during an incremental cycling exercise. Methods: 71 male athletes aged from 16 to 34 years old from Macau Team and Macau Youth Team, which included 6 different sports such as long-distance running, handball, basketball, football, dragon boat and sprint, were recruited for this study. After 3 minutes warm up, each participant performed continuous incremental cycling exercise on a Monark stationary mechanically braked cycle ergometer beginning at an intensity of 50W power output, and then the power output was increased by 50 W every 3 minutes in each exercise intensity stage until the subjects can not keep up with the workloads. Blood lactate, Borg 20-point RPE scale and heart rate responses were recorded at the end of each stage. Results: RPE and HR (r = 0.828, p<0.01), RPE and Bla (r = 0.742, p<0.01), Bla and HR (r = 0.826, p<0.01)were significantly related to each other during the continuous incremental cycling exercise. Blood lactate levels can be regressed by age, RPE and HR, Bla level = 0.105 * RPE + 0.061 * HR + 0.031 * Age - 6.128. 69.5% of variance can be explained by this regression equation. Conclusion: RPE, HR and Bla are closely related with each other during incremental cycling exercise and RPE, age and HR can predict blood lactate level well.