PER and TIM are two important clock proteins in Drosophila. In the previous research, PER and TIM were considered to combine as heterodimers in the cytoplasm, then the heterodimers PER/TIM can be transported into the nucleus. But the experimental research, made by Pablo Meyer et al. in 2006, has indicated that PER/TIM heterodimers dissociated in cytoplasm, and then PER and TIM can be independently transferred into the nucleus in a narrow time frame. This paper revised the circadian regulation model of Drosophila according to the above experimental result. The revised model considers the process of the transcription and translation of gene per and tim, the protein post-translational modification, the separate entry of the secondary phosphorylation of protein PER (P2) and TIM (T2) into the nucleus and the subsequent regulatory process. Then we calculate the periodic oscillation of the revised model, and determine the values of new parameters introduced by the modification process. Subsequently we calculate the oscillation rhythm of the revised model. It is found that the revised model exhibits similar properties as original model. That is to say, the oscillation is periodic and the rhythm is close to 24h under the condition of DD and LD, but the oscillation is damping under the condition of LL. The results reflect the rationality of the revised model. On the other hand the revised model shows more dependencies on the parameter symmetry than the original model. The detailed explanation for this phenomenon needs further work.