Objective：To observe and compare the state of marginal microleakage between fluoride-containing resin sealant and glass ionomer sealant in vitro. Methods：Totally 30 newly extracted noncarious human the third molars were randomly divided into three groups with 10 samples in each group. The occlusional surfaces of the specimens were sealed with ClinproTM Sealant，Fuji Ⅸ GP and Concise，respectively. After 125 cycles of thermo-cycling，all specimens were immersed in 1% solution of methylene blue dye for 48 h then the microleakage of each specimen was measured under stereomicroscope. Results：Results of dye penetration revealed that there was no significant difference in microleakage among two test groups and control group（P >0.05） and there was no significant difference between two test groups（P >0.05），either. Conclusions：All three types of pit and fissure sealants showed lower microleakage. The tooth surface fitness of glass ionomer cement（Fuji Ⅸ GP） is comparatively similar to resin sealants，with satisfactory sealing ability. It’s worth promoting glass ionomer material as pit and fissure sealant in clinics.