Abstract: Objective To evaluate the clinical effect of light cure Beautifil flowable（LCBF） in molar occlusal pit and fissure. Methods 720 the first up and down permanent molars in 360 patients aged from 6-10 years were treated with LCBF in occlusal pit and fissure. The opposite permanent teeth were treated with light cure pit and fissure sealant LCFS as the controls. The patients were followed up for 3 years. Results The remain rate（%） of LCBF sealant after 1, 2 and 3 years was 93.86%, 84.58% and 79.72% respectively. It was higher than that of LCFS（P＜0.01）. The incidence rate（%） of caries in LCBF treated teeth was 0, 0.15% and 0.87%, and lower than that of the controls（P＜0.05）. Conclusion Beautifil flowable can be used as pit and fissure sealant to prevent caries.