In order to quickly and accurately determine the position of gas leakage source, the weighted centroid method is proposed. The gas sensors are placed near the gas leakage detection area and the data collected from wireless sensor network nodes is sent to the coordinator through ZigBee wireless sensor network. Then, the packaged data coming from the coordinator is passed to the main processor and the location of the gas source is calculated by the main processor based on the weighted centroid method by using the measurement results and the results are displayed. Experiments with ethanol vapor as the target gas are conducted and the relative positioning error is no more than 6% in a area of 4 m×4 m, and the correction of the gas source position method is illustrated.