Objective To investigate the application of levels of serum human chorionic gonadotropin (HCG) and alpha fetoprotein (AFP) combined with magnetic resonance imaging (MRI) in implantation and classification diagnosis of placenta previa. Methods 65 patients with placenta previa implantation in the hospital were enrolled in the placenta previa implantation group. The other 60 patients with single placenta previa in the same period were enrolled in the single placenta previa group. 50 parturients without placenta previa or implantation were enrolled in the control group. The serum HCG, AFP and MRI examination were performed on parturients in the three groups. The results of placenta previa implantation and classification diagnosis with different examination methods were compared. Results The levels of serum HCG and AFP in the placenta previa implantation group were significantly higher than those in the single placenta previa group and the control group (P<0.05). The levels of serum HCG and AFP in the penetrating patients were significantly higher than those in the adhesion type and implanted type patients (P<0.05). The serum HCG level of the implanted patients was significantly higher than that of the adhesion type patients (P<0.05). The implantation detection rates of adhesion placenta, implanted placenta and penetrating placenta with HCG with AFP and MRI were 96.55%, 95.65% and 100%, respectively, all higher than those with either of the three. Conclusion Serum HCG, AFP combined with MRI can identify the placenta previa implantation and type of placenta implantation.