Abstract: In process of node location in wireless sensor networks, location information of unknown nodes is often obtained by trilateral location algorithm combined with ranging algorithm．Aiming at problems such as low positioning accuracy, small application range and increasing node energy consumption caused by multiple transmission of positioning data packets, a trilateral positioning algorithm was proposed, which corrected and compensated measuring distance．Compared with common method of sending multiple positioning packets and then filtering calculation to reduce positioning errors, lognormal-model was adopted to measure distance between nodes and send fewer positioning packets．By judging relative positions of three-anchor node circles, three cases of node circles disjoint due to large range error were corrected and compensated．Coordinates of unknown nodes were calculated by using trilateral positioning algorithm based on centroid algorithm．Feasibility and positioning accuracy of this algorithm was verified by building Matlab simulation tests．Test results showed that modified and compensated trilateral positioning algorithm proposed comprehensively considered the relationship among positioning accuracy, algorithm complexity and node power consumption, and has a wider application range with positioning error less than 15%．