Falls and their corresponding physiological parameters monitoring are very important for the elder health care. A body sensor network (BSN) system working in 2.4 GHz with a star topology is proposed in this paper. The body parts of the BSN used CC2520 chips for communication, deploying an acceleration sensor node on the head, a pulse sensor node on the wrist, two plantar pressure sensor nodes on the ankle and a sink node which has the acceleration sensor function on the waist respectively. It collected the human real-time information of the motion acceleration, the plantar pressure and the pulse. The sink node communicated with a remote computer through the Bluetooth module. The BSN system test result shows it can accurately detect the fall event and the pulse change.