noneEnter The effects of cold acclimation on Fopius arisanus (Sonan) were studied. The results showed that the supercooling point (SCP) and freezing point (FP) of both female and male adults of F. arisanus would increase first then decrease as the extension of time. The SCP and FP would reach the highest at 24 h (for female the SCP was -7. 66 [plus or minus] 0. 27[degree]C and FP -2. 95 [plus or minus] 0. 16[degree]C; for male the SCP was -7. 22 [plus or minus] 0.31[degree]C and FP -2.58 [plus or minus] 0. 23[degree]C) and the lowest at 72h (for female the SCP was -9. 76 [plus or minus] 0. 30[degree]C and FP - 5. 08 [plus or minus] 0. 23[degree]C; for male the SCP was - 8. 98 [plus or minus] 0. 28[degree]C and FP - 4. 28 [plus or minus] 0. 28 [degree]C), the highest had significant difference however the lowest had no significant difference compared to the control. The SCP and FP of males' were higher than females' during the time. The SCP and FP of overwintering females and males of F. arisanus were lower than the control from the last December to the next March and both reached the lowest at the next March (for female the SCP was -12. 24 [plus or minus] 0. 23 [degree]C and FP -6.65 [plus or minus] 0. 24[degree]C; for male the SCP was - 11. 37 [plus or minus] 0. 26 [degree]C and FP -5.81 [plus or minus] 0. 24[degree]C). At the same time the SCP and FP of females' were lower than males'. The parasitism rate of overwintering females and the emergence rate of offspring would decrease first then increase but still be lower than the control. Both would reach the lowest during the next February (The parasitism rate was 37. 12 [plus or minus] 1. 04 and the emergence rat was 9. 68 [plus or minus] 0. 47) and there had significant difference compared to the control.