Objective: To investigate the value of ultrasound and magnetic resonance imaging (MRI) in prenatal diagnosis of fetal spina bifida closed.Methods: A total of 26 fetuses with clinically confirmed closed spina bifida were selected as the study group, and 38 fetuses without nervous system abnormalities were selected as the control group. The diagnostic results of prenatal ultrasound, MRI and combined examination were retrospectively analyzed in the study group and the control group. The sensitivity and specificity of different examination methods were compared, and the efficiency was checked by comparing the area under the ROC curve. Results: 26 cases of spina bifida were diagnosed clinically after delivery, 24 cases were diagnosed accurately before delivery, 20 cases were diagnosed by ultrasound, 17 cases were diagnosed by MRI, 24 cases were diagnosed by combined diagnosis, 2 cases were missed diagnosis（1 case of tethered cord and 1case of furicular sinus）. There were significant differences in sensitivity, specificity, positive predictive value, negative predictive value and accuracy of the three methods in the diagnosis of closed spina bifida (P<0.05). The areas under ROC curves of the three methods were 0.8964, 0.8757 and 0.9120, respectively, and the differences were statistically significant (P<0.05). Conclusion: Ultrasound can be used as the first examination for the diagnosis of fetal spina bifida in primary hospitals, MRI as a supplementary examination, the combination of the two examination can be more effective in the detection of fetal spina bifida.