Abstract： Objective To explore factors related to circulating gas embolism occurrence and causes of symptoms during hysteroscopic surgery. Methods In the 34 cases undergoing hysteroscopic surgery,conditions of circulating gas embolism were monitored and leveled by the Doppler. Results Twenty patients of all 34 patients had gas embolism, and 6 patients had symptoms; 2 out of 5 were symptomatic in grade Ⅱ gas embolism group, while 4 out of 6 in grade Ⅲ. Symptoms were positively correlated with levels of gas embolism. In 26 cases whose operation time was over 30 minutes, gas embolism occurred in 18 patients, and 6 patients had symptoms,which showed increasing probability of gas embolism levels and clinical symptoms. No gas embolism occurred when the perfusion volume was<2000 mL,while 5 out of 10 cases with perfusion volume 2000 to 3000ml and 15 out of 20 with over 3000ml developed gas embolism, 1 and 5 cases had symptoms respectively. The incidence of gas embolism and occurrence of clinical symptoms increased significantly with the perfusion volume. Conclusions A close relationship between the occurrence of clinical symptoms and gas embolism is observed. Low-degree gas embolism has no serious damage. The degree of gas embolism can be used as an option to predict the occurrence of serious complications.The level of gas embolism is related to the clinical symproms.