Abstract: Objective To analyze the influencing factors of defecation function in patients with low rectal cancer after laparoscopic assisted transanal total mesorectal excision(TaTME). Methods The clinical data of 87 low rectal cancer patients with TaTME in our hospital was collected and was retrospectively analyzed. The postoperative 3-month defecation function was evaluated by Low Anterior Resection Syndrome(LARS)Scale. The patients were divided into LARS group(scored≥21, n=42)and LARS-free group(scored≤20, n=45)according to their defecation functions. The general situation questionnaire was designed, and the univariate and multivariate analysis were used to identify the influencing factors of defecation function in patients with low rectal cancer after TaTME. Results The results of multiple non-conditional Logistic regression analysis showed that the distance between anastomosis and anal margin smaller than 2 cm, anal sphincter injury, distance between tumor and anal margin below 5 cm, and neoadjuvant chemoradiotherapy may be the influencing factors of defecation function in patients with low rectal cancer after TaTME(OR>1, P<0.05). Conclusion The defecation function of patients with low rectal cancer after TaTME is affected by varied factors, among which the distance between anastomosis and anal margin, anal sphincter injury, distance between tumor and anal margin, and neoadjuvant chemoradiotherapy are the main influencing factors. Therefore, close focus on these factors should be done and corresponding intervention measures should be given to these patents in clinic.