A femtocell includes a memory, a transmitter, a receiver and a controller. The memory stores access probability values in different time periods, and a comparison table of power saving rates and probability thresholds. Each power saving rate is a proportion of the time periods whose access probability values are not more than a predetermining probability threshold and all time periods. The controller includes a setting module setting the predetermining probability threshold, a time module getting a current time and a corresponding current time period, a user identifying module determining whether the user accessing the femtocell through the receiver is a registered user, a switching module controlling the transmitter through determining whether the access probability value at the current time period is less than the predetermined probability threshold, a statistic module calculating the access probability value at the current time period according to the identifying result of the user identifying module.