Objective To explore the methods of grading the degree of uterine adhesion in the rat model of uterine adhesion. Methods 10 cases of a rat model of uterine adhesion were established by the double injury method. HE staining was used to observe the paraffin sections. Masson staining was used to compare the uterus morphology, the uterine cavity area, and the degree of adhesion. The sections were classified into three grades according to the area of the uterine cavity for comparative analysis. Results The average uterine cavity area and uterine cavity area/endometrial layer area of rats in the model group were smaller than those of rats in the blank group (P < 0.01); the ratio of uterine cavity area/endometrial layer area was categorized into three grades: Ⅰ, Ⅱ, and Ⅲ, and there was a significant difference between the grades (P < 0.05, P < 0.01). Conclusion The uterine cavity area/endometrial layer area of rats with uterine adhesion may reflect the grading difference in the degree of uterine adhesion. It can be used as one of the grading evaluation criteria in the rat model of uterine adhesion, which can provide significance for diagnosing grading in the model of uterine adhesion.