When Femtocell and UMTS co-exist in the two-tier communication environment, interference between the two systems may bring about the problem of communication deadzone. The way to reduce the scale of deadzone and to alleviate deadzone effect to users is one of the major issues in the development of communications. Based on the properties of the procedure and the messages during user registration and handover that UE used to acquire access right to a base station, a mechanism is proposed in this article to adjust the transmission power of a FAP automatically to mitigate the deadzone effect for UMTS users in the two-tier environment. The proposed method can downscale a probable Femtocell deadzone automatically just before a UE reaches it, therefore alleviating the probable deadzone effects on the UE.