With the increased demand of broadband wireless communication networks, users have an increasing need of the wireless broadband service coverage and the wireless access quality. To solve this problem, several novel technologies are proposed. One of these technologies is femtocells. A femtocell can be used to increase the coverage of wireless broadband service indoors or at hotspots and raise both data transmission rate and access quality. Although the use of femtocells can greatly benefit, deploying large number of femtocells consumes tremendous energy. In order to respond to the problem of global climate change, energy saving is always an important issue. This paper discusses how to minimize the energy consumption of femtocells, optimize the energy efficiency of femtocells, but still provide both the same data transmission rate and wireless broadband service coverage. In this paper, we propose a green handover and dynamic femtocell wake up approach. In default, femtocells are stay in idle mode when no one connecting to it. They transit to active mode only when detecting User Equipments (UEs) and the power efficiency of using the femtocell to transmit data is better than the macrocell. By this way, not only users can benefit from the femtocells but also femtocells can reduce unnecessary power consumption. Simulation results show that, in bot 3G/4G wireless communication networks, our method performs better than the previous methods in power consumption, power efficiency and throughput.