The invention relates to a sparse wireless sensor network positioning method in a noisy environment. A positioning technology is a factor of the wireless sensor network and is used in invasive detection in water quality, atmosphere monitoring, health monitoring, and militaries. A positioning technology in the prior art is defective in that a sensor network cannot achieve positioning without a high node density so that a plenty of sensor nodes have to be disposed to satisfy a node density requirement. The sparse wireless sensor network positioning method in the noisy environment comprises a transmission range model, a method principle, and a three-layer positioning algorithm bi-tri. The positioning method comprises a two-side positioning method and a three-side positioning method. The three-layer positioning algorithm bi-tri is composed of three stages including local positioning, cluster positioning, and global absolute location positioning or global relative location positioning. The method prevents a problem that a high overturn probability is generated when errors exist because a low node positioning ratio caused by a low node density is in the sparse network.