Progress in medicine has extensive relation with other fields of science and technology.the through effect of the development of various sciences on human"s life and presenting health care services shows this relation. Emersion of body sensor network is one of these advances. Wireless body sensor networks will revolutionize health care services by remote and continuous monitoring. Hence it is expected that preventing and early detecting of disease will be added to the current healthcare systems which are mostly based on disease management. Due to the raising of the costs of health care and growth in life expectancy, wireless sensor networks are offering the next evolution in biometrics and healthcare monitoring applications. By wireless body sensor network systems, a hospital can monitor physiology signals for 24h without disturbing the patient. According to the attempts for convenience of users in all parts of life , the patient" vital signs can be observed out of hospital environment .the main purpose of body sensor networks is to transmit health information of users to medical center or physician in real time without any inconvenience for users. These sensors can measure different vital signs of patients like blood pressure, body temperature, pulse oxygen, heart beat, and other similar parameters. These research introduces medical sensor network and requirements of these networks and proposes a solution for power reduction as the main concern in body sensor networks. we propose a new method which work based o the compressed sensing theory.Compressed sensing is a new context in signal processing whose main idea is the simultaneous sampling and compression. It makes it possible to recover the signals in sampling rates which are lower than the Nyquist rate. All sensors can be simulated using compressed sensing. For evaluating error diagnosis of physician , a field study was carried out on the reconstructed signals. the survey conducted in this thesis show that Despite many errors in signal reconstruction, error diagnosis of physician is an acceptable level. Keywords: Wireless sensor network, Body sensor network, Power consumption, compressed sensing