The present study aimed to evaluate the incidence and risk factors of severe low anterior resection syndrome (LARS) in patients with rectal cancer undergoing sphincter-preserving resection, and to provide the clinical basis and reference for the treatment of rectal cancer and the prevention of LARS. Studies on the incidence and risk factors for severe LARS in patients with rectal cancer undergoing sphincter-preserving resection were searched using PubMed, Embase, Cochrane Library, Scopus and Web of Science, according to the inclusion and exclusion criteria. After evaluating the study quality and extracting relevant data, RevMan 5.2 and STATA software were used to conduct a meta-analysis. A total of 12 articles were considered eligible for the present meta-analysis. Within these articles, there were 3,877 cases of sphincter-preserving resection for rectal cancer and 1,589 cases of severe LARS; the incidence of severe LARS was 40.99%. The results of the meta-analysis revealed that sex [female; odds ratio (OR), 6.54; 95% CI, 3.63–11.76; Z, 6.27; P<0.00001], radiotherapy and chemotherapy (OR, 3.45; 95% CI, 2.29–5.21; Z, 5.91; P<0.00001), total mesorectal excision (TME; OR, 4.39; 95% CI, 3.32–5.79; Z, 10.41; P<0.00001), and distance between tumor and anal margin (OR, 2.74; 95% CI, 0.86–8.72; Z, 1.70; P<0.00001) may be the risk factors for severe LARS.