Objective To investigate the therapeutic effect and safety of low-dose heparin therapy for heat stroke with pre-diffuse intravascular coagulation (pre-DIC). Methods 35 cases of heat stroke with preDIC were randomly divided into two groups, 18 cases were treated with low-dose heparin therapy (treatment group, n = 22, given heparion by 70U/kg for 3 days, 24 hours of continuous pump), 17 cases were treated with conventional therapy(control group). The incidence of DIC and mortality in two groups were observed and compared. Results Incidence of DIC and mortality in treatment group were significant lower than those in control group(P ＜0. 05). After the treatment group therapy, a statistically significant increase BPC (P＜ 0. 01). No significant differences APTT PT, (P ＞ 0.05). Conclusion Low-dose heparion is applied early in heat stroke patients in pre-DIC stage, which could not only prevent efficiently DIC, but also diminish mortality.