According to the practical operation of coastal power plant cooling system, a simulation study was conducted on the effects of residual heat and chlorine in the cooling water on Calanus sinicus. The results showed that the thermal tolerance of C. sinicus to the cooling water was decreased with increasing exposure duration but increased with increasing acclimation temperature. When the acclimation temperature was 16 degrees C-27 degrees C, the lethal temperature of C. sinicus under thermal shock for 15, 30 and 45 min was 29.9 degrees C-31.7 degrees C, 29.4 degrees C-31.0 degrees C and 28.9 degrees C-30.3 degrees C, and that of C. sinicus continually exposed to increasing temperature for 24 and 48 h was 26.9 degrees C-28.5 degrees C and 26.4 degrees C-28.0 degrees C, respectively. When the acclimation temperature increased to a certain degree, the thermal tolerance of C. sinicus maintained at a stable level. The toxicity of residual chlorine on C. sinicus enhanced with increasing acclimation temperature, temperature increment, and exposure duration.