This study was undertaken to evaluate the preoperative correlation of serum markers and pelvic adhesions in endometriosis patients, and to explore their clinical value for prediction. Preoperative basic serum laboratory test and CA 125 were analyzed, and the adhesion score calculated. The group with less than 28 points was defined as a mild adhesion group, and a score of 28 or more as a severe adhesion group. CA 125 was significantly higher in severe adhesion group than mild adhesion group. CA 125, size of largest cyst and WBC are associated with pelvic adhesions. The adhesion score was significantly higher in the CA 125 ≥ 35 U/mL group than the CA 125 < 35 U/mL group. Patients with preoperative CA 125 higher than 35 U/mL are at high risk for pelvic adhesion.