AIM:To compare the effect of restored molars meiso-occlusal cavity of filling with inlay and amalgam. METHODS: 30 selected mandibular molars with meiso-occlusal cavity were restored with inlay and amalgam respectively, observing closely for two years and comparing the effect. RESULTS: The successful restorations with inlay have 28 cases (93.33%) , failure in 2 cases(6.67%). The successful restorations with amalgam have 21 cases (70.00%), failure in 9 cases (30.00%). CONCLUSION: The effect of restored mandibular molars meiso-occlusal cavity with inlay is clearly higher than the amalgam. [