A Hybrid Multi-channel MAC protocol with Virtual Mechanism and Power Control for Wireless Sensor Networks (HM-VMPC) is designed and implemented in this paper. This kind of protocol integrates dynamic channel assignment mechanism and quasi-reservation mechanism effectively. It employs a virtual MAC frame mechanism to support larger network layer packets, and a multi-channel virtual carrier sensing mechanism to estimate idle or busy channels effectively, and has the function of intelligent power control which adjusts the transmission power levels automatically according to the distance among network nodes, therefore reduces the energy consumption and prolongs the life of the entire network. This protocol provides proper solution to the hidden and exposed terminal problem in wireless sensor network, and improves the network performance. HM-VMPC is compatible with the physical layer of IEEE 802.15.4 standards, and is able to run on SARD (Sensor Applications Reference Design) board from Freescale company. The performance of HM-VMPC is tested and compared with other classical MAC protocols. Experiments show that HM-VMPC is suitable to solve the problem of hidden and exposed terminal in multi-hop wireless networks, and can control the power more effectively to reduce the energy consumption of network nodes for prolonging the life of the entire network.