The invention belongs to the fire positioning field, particularly relates to a fire positioning method on the basis of smoke concentration, is on the basis of a wireless sensor network and carries out positioning estimation on a fire source point through utilizing smoke concentration acquired by the concentration sensor on the basis of a smoke diffusion model. The method comprises steps that 1, the smoke diffusion model under the no wind environment is established, and a relationship between gas concentration under the no wind condition and a distance is determined; 2, on the basis of weight fusion of the gas concentration and a least square method, a fire source zone is positioned; 3, on the basis of a K-means cluster method, cluster analysis on the fire source zone positioned in the step 2 is carried out, and a fire source point is determined. The positioning method is applicable to conditions that a fire is at an early stage, a roof is flat, a wind speed is relatively small, and only a single fire source point exists, a smoke flow is taken as a two-dimensional plane, through the fire positioning method, a place below the zone of a positioning result is taken as a fire generation zone. The fire positioning method has advantages of low energy consumption, timeliness, low cost, interference resistance and strong practicality.