To illustrate the effect of sudden increase and drop in temperature on immunity in normal conditions, and to lay the foundation of a further study on effect of extreme climate change on human bodies. Methods:Manual simulation system was adopted to simulate sudden increase and drop in temperature. Blood tests were applied for measuring serum MT, IL-1, IL-6 and T-lymphocytes of golden hamsters after 24 hours and 72 hours of intervention respectively. Results:1) Compared with the normal climate group, IL-1and IL-6 levels in serum increased significantly during the 24 hours after a sharp increase in temperature (P<0.01). MT, IL-1 and IL-6 levels in serum decreased, almost the same as the normal control group content after a 72 h sharp increase in temperature； IL-1 levels increased greatly (P<0.01) after a 24 h sudden drop in temperature. MT, IL-1 and IL-6 levels in serum were significantly increased after a 72 h sudden drop in temperature. All data above showed statistical significance.2) Compared with the normal climate group, CD3+ and CD4+ levels significantly increased（P<0.05）after 24 hours of sharp increase in temperature. CD8+ level decreased, but the difference was not statistically significant（P>0.05）. After 72 h, CD3+ and CD4+ levels were normal again, but CD8+ level continued to reduce, and the difference was statistically significant. CD3+ level increased and there was a significant difference after 72 h. CD4+ Contents had no significant change. CD8+ level significantly decreased after 24 h of intervention（P<0.05）and recovered to normal level when 72 h. CD4+/CD8+ level tended to increase in sudden change of temperature（P<0.05）with statistical significance.3) After 24 h increase of temperature, MT and IL-6, CD3+ and CD8+ had positive correlation, and correlation indexes were 0.779, 0.836, 0.828; after 72 h increase of temperature, MT and CD3+,CD4+ and CD8+ had positive correlation, and correlation indexes were 0.923,092,0.883, 0.792; after 24 h decrease of temperature, MT and CD3+,CD4+ and CD8+ had positive correlation, and correlation indexes were 0.86,0.818, 0.807, 0.783; after 72 h decrease of temperature, MT and IL-1,IL-6, CD3+, CD4+ and CD8+ had positive correlation. Conclusion:Serum MT, IL-1, IL-6 and CD4+/ CD8+ levels all increased significantly in sudden change of temperature, which may be one of the main mechanisms of effect of abrupt climate changes on immunity. MT and CD3+, CD4+ and CD8+ had significantly positive correlation, which may because of more secretion of MT, increased content of MT in serum, and the multiplication rate of T-lymphocytes improved, thus the immunity was developed to cope with sudden change of temperature.