The invention discloses a polyhedral grid coverage searching method. The polyhedral grid coverage searching method comprises the following steps: firstly, randomly distributing n sensors in a searching domain; building a common coordinate system by taking coordinates of the sensors at different discrete moments k as common variables q(k), and defining three-dimensional grids by specific q(k) and sensor perception ranges R to obtain a three-dimensional grid layout of the searching domain; detecting a target once the sensors move to one vertex from an initial position, and sharing target information and access vertexes with adjacent sensors; judging whether adjacent vertexes are all accessed or not one sensor by one sensor, and if not, randomly moving to non-accessed vertexes until all adjacent vertexes are accessed; then, randomly moving to adjacent vertexes and judging whether searching is finished or not, and if so, outputting a searching result; otherwise, continually moving for searching. The method is applied to a searching system based on a wireless sensor. Through adoption of the method, three-dimensional space searching of any number of targets based on any number of sensors can be realized, and the searching efficiency is high.