Abstract: Objective Various approaches were adopted to treat the surfaces of artificial demineralized enamel lesions. By observing the penetration effects we could get more viable foundation for the clinical application. Methods 32 intact first premolars and first molars were selected from orthodontic extraction. They were placed in the artificial demineralization solution for 14 days to form initial artificial enamel caries. The teeth were divided into four groups randomly, and surfaces of teeth in each group were dealed with 15% hydrochloric acid, 37% phosphate and polished by Opalustre, stained by NaFl, penetrated with Icon and processed with light solidification. By observed under CLSM microscope, the impact of four treatment methods on penetration depths was compared. Results There were significant differences in depths of penetration between hydrochloric acid group and phosphoric acid group（P<0.05）.The hydrochloric acid group got a better result. There were significant differences between the two polished groups in the depths of penetration（P<0.05）. Increasing grinding time could increase the penetration effect. There were significant differences in penetration depths between polished group 2 and hydrochloric acid group or phosphoric acid group（P<0.05）. Polishing 40 seconds with Opalustre produced a better result. Conclusions The highly calcified layer is a barrier impeding the Icon to penetrate. The penetration effect of the hydrochloric acid treatment is better than that of the phosphoric acid treatment. By grinding for forty seconds of the barrier, the penetration effect is significantly better than that dealt for twenty seconds. So grinding can be considered as an alternative or a complement of pretreatment method in clinical treatment.