Objective：To analyze the effects of fluor protector on microhardness and morphology of cold light bleached enamel. Meth－ods：Totally 40 premolars extracted for orthodontic reasons were selected，whose buccal surfaces were made into enamel slabs（5 mm×5 mm）. Those enamel slabs were subjected to group A，B，C and D randomly. Group A’s microhardness before bleaching，after bleach－ing and after using fluor protector were evaluated. Groups B，C and D were evaluated under scanning electronic microscopy. Group B was bleached，group C used fluor protector after bleaching and group D was taken as blank control group. Results：Microhardness of enamel was decreased significantly after bleaching compared with that before bleaching（P<0.05），microhardness of bleached enamel with fluor protector was higher than that without fluor protector，however，microhardness of enamel before bleaching and after using fluor protector were not statistically significant（P >0.05）. Scanning electronic microscopy（SEM） indicated the roughness of enamel surface was increased and some random depression spots became noticeable. After using fluor protector，the surface of enamel became less rough and sediments were seen. Conclusions：Using fluor protector after cold light bleaching makes the microhardness and mor－phology of enamel recover quickly.