Objective To explore risk factors of colorectal lateral spreading tumors (LST) combined with high grade intraepithelial neoplasm (HGIN) or cancerization in elderly patients. Methods A retrospective study was conducted on data of 212 aged patients (≥60 years) with colorectal LST admitted to Fujian Provincial Hospital from January 2013 to June 2019. The correlation between pathology and general clinical characteristics (including age, gender, body mass index, comorbidity, history of smoking, drinking, and administration of antithrombotic drugs, level of blood lipids and carcinoembryonic antigen) and endoscopic features (lesion location, lesion size, and endoscopic morphological classification) were analyzed. Risk factors of LST combined with HGIN or cancerization in elderly patients were summarized. Results The 212 cases included 119 males and 93 females, aged 68.76±6.37 years. The size of lesions was 26.10±15.64 mm. The rate of endoscopic resection reached 96.2% (204/212), and only 8 (3.8%) cases need surgical resection. Curative resection rate of endoscopy was 99.5% (203/204). The postoperative pathology revealed that 74 cases (34.9%) were HGIN and 16 (7.6%) were carcinoma. In the univariate logistic regression analysis, age, gender, body mass index, smoking history, alcoholic history, comorbidity, antithrombotic consumption, blood lipid, carcinoembryonic antigen value were not risk factors for LST combined with HGIN or cancerization (P>0.05). Lesion size (P<0.001), location (P=0.002), and morphology (P<0.001) were risk factors. In the multivariate logistic regression analysis, the lesion size ≥20 mm (P=0.001), granule mixed type (P=0.020, OR=2.624, 95%CI:1.161-5.933) or pseudo depressed type in morphology (P=0.012, OR=10.009, 95%CI:1.667-60.080) were the risk factors for LST combined with HGIN or cancerization in the elderly. Conclusion The lesion size and morphology are the independent risk factors for LST combined with HGIN or cancerization in aged patients (age≥60 years), so more attention should be paid to colonoscopy and early intervention.