Objective: To analyze the correlation between the expression of estrogen receptor (ER), progesterone receptor (PR), tumor protein 53 (P53), and epidermal growth factor receptor 2 (HER2) with tumor grading and depth of muscle infiltration in patients with endometrial cancer. Methods: A study was conducted on 72 patients with endometrial cancer admitted from January 2021 to May 2025. They were divided into a malignant group, and 72 patients with benign uterine lesions with complete pathological data during the same period were selected as the benign group. Immunohistochemistry was used to detect the expression of ER, PR, P53, and HER2 in the endometrial tissue of patients, and the correlation between ER, PR, P53, and HER2 and tumor grading and muscle infiltration depth was analyzed. Results: The positive rates of ER, PR, P53, and HER2 in the malignant group were 56.94%, 52.78%, 37.50%, and 15.28%, respectively. The positive rates of ER and PR in the malignant group were lower than those in the benign group, while the positive rates of P53 and HER2 were higher than those in the benign group (P<0.05); There were significant differences in the positivity rates of ER, PR, P53, and HER2 among patients with different tumor grades. The positivity rates of ER and PR were G1, G2, and G3 from high to low, while the positivity rates of P53 and HER2 were G3, G2, and G1 from high to low (P<0.05); There was no significant difference in the HER2 positivity rate among patients with different depths of muscle infiltration (P>0.05), while there were significant differences in the positivity rates of ER, PR, and P5. The positivity rates of ER and PR ranged from high to low as no muscle infiltration, <1/2 muscle infiltration, and ≥1/2 muscle infiltration, P53, the positive rates from high to low were ≥1/2 muscle layer infiltration,<1/2 muscle layer infiltration, and no muscle layer infiltration (P<0.05); ER and PR are negatively correlated with tumor grading and depth of muscle infiltration, P53 is positively correlated with tumor grading and depth of muscle infiltration, and HER2 is positively correlated with tumor grading (P<0.05). Conclusion: ER, PR, P53, HER2 are closely related to tumor grading and depth of myometrial invasion in patients with endometrial cancer. The above indicators can be used as effective indicators for evaluating the occurrence, development, and invasion of endometrial cancer.