Objective To investigate the clinicopathological characteristics of early gastric cancer with mixed histological staging, and to analyze the prognostic effect of endoscopic submucosal dissection (ESD) for early gastric cancer. Methods Clinical data of early gastric cancer patients treated with ESD in Gansu Wuwei Cancer Hospital from January 2011 to March 2020 were collected, and clinicopathological characteristics of patients with mixed-type early gastric cancer were analyzed by descriptive statistical methods. The clinical effects and influencing factors of ESD on early gastric cancer were analyzed by logistic regression. Kaplan-Meier was used to estimate the survival rate, and log-rank test was used to compare the survival rate. Results A total of 269 patients (280 lesions) were included in this study, including 216 males (80.30%) and 53 females (19.70%), with age of 60.43±8.01 years. There were 25 lesions (8.93%) of mixed early gastric cancer, 248 lesions (88.57%) of differentiated early gastric cancer, and 7 lesions (2.50%) of undifferentiated early gastric cancer. Compared with differentiated and undifferentiated early gastric cancer, the lesion site of mixed early gastric cancer was mainly located in the upper 1/3 of the stomach [64.00% (16/25), 40.73% (101/248) VS 0.00% (0/7), χ2=10.211, P=0.006], the proportion of the lesion size ≤2 cm was relatively small [52.00% (13/25), 80.65% (200/248) VS 85.71% (6/7), χ2=11.173, P=0.004], and the proportion of infiltration depth in the mucosa was lower [52.00% (13/25), 85.48% (212/248) VS 57.14% (4/7), χ2=20.019, P<0.001], the proportion of positive vertical resection margin was relatively high [20.00% (5/25), 2.82% (7/248) VS 0.00% (0/7), χ2=16.657, P<0.001], the proportion of vascular invasion was higher than that of differentiated carcinoma but lower than that of undifferentiated carcinoma [36.00% (9/25), 2.42% (6/248) VS 42.86% (3/7), χ2=58.413, P<0.001], the complete resection rate was lower [76.00% (19/25), 93.15% (231/248) VS 100.00% (7/7), χ2=9.497, P=0.009], the curative resection rate was lower than that of differentiated early gastric cancer, but higher than that of undifferentiated early gastric cancer [48.00% (12/25), 89.52% (222/248) VS 42.86% (3/7), χ2=39.757, P<0.001], and the proportion of eCura grade C2 was higher than that of differentiated cancer, but lower than that of undifferentiated cancer [48.00% (12/25), 5.65% (14/248) VS 57.14% (4/7), χ2=58.766, P<0.001]. The results of multivariate analysis showed that the larger lesions (P=0.004, OR=0.539, 95%CI: 0.354-0.822) was the risk factor for curative resection. In terms of infiltration depth, mucosal (P=0.001, OR=51.799, 95%CI: 5.535-84.768) and submucosal 1 (P<0.001, OR=29.301, 95%CI: 24.694-73.972) were protective factors for curative resection compared with submucosal 2. In terms of differentiation degree, compared with mixed type, differentiated type (P=0.024, OR=3.947, 95%CI: 1.195-13.032) was the protective factor for curative resection, while undifferentiated type (P=0.443, OR=0.424, 95%CI: 0.048-3.788) showed no difference between curative resection and mixed type. During the follow-up, 7 patients died. The overall survival time was 114.42±0.97 months, and the 5-year survival rate was 97.10%. There was no significant difference in the survival rate of early gastric cancer patients with different degrees of differentiation (χ2=0.434, P=0.805). The survival rate of early gastric cancer patients with or without curative resection was significantly different (χ2=4.081, P=0.043). Conclusion Mixed early gastric cancer patients show high margin positive rate, vascular infiltration, and less curative resection than differentiated early gastric cancer. Therefore, the process of treating mixed early gastric cancer should be more rigorous. The long-term survival prognosis of early gastric cancer after ESD treatment is promising.