The present invention discloses an approximate point-in-triangulation test (APIT)-based wireless sensor network node positioning method. The method comprises a tenth step of anchor node position information transceiving; a twentieth step of node distance acquisition; a thirtieth step of unknown node estimation coordinates calculation; a fortieth step of unknown node position screening; a fiftieth step of centroid polygon selection; and a sixtieth step of unknown node true coordinates determining. In the tenth step, an anchor node sends position information of the anchor node, and an unknown node receives the position information of the anchor node. In the twentieth step, a distance between the unknown node and the anchor node is calculated according to signal strength. In the thirtieth step, the unknown node estimation coordinates are calculated according to the distance between the unknown node and the anchor node. In the fortieth step, a triangular region including the unknown node is screened by using an improved APIT algorithm according to the estimation coordinates. In the fiftieth step, the whole wireless sensor network is divided into multiple mesh regions, and a polygonal mesh region with the highest mesh region value is selected as the centroid polygon. In the sixtieth step, the unknown node true coordinates are obtained according to the centroid polygon. The node positioning method has high accuracy, high efficiency and low cost.