Regarding the low localization accuracy and coverage of the Approximate Point-In-Triangulation Test (APIT) algorithm, this study proposes a hybrid localization algorithm based on the APIT and genetic algorithms for Wireless Sensor Network (WSN). This algorithm improves localization accuracy by the APIT algorithm optimized with a comparison of segmentation methods and enhances localization coverage by the genetic algorithm. Simulation results show that in comparison with the APIT algorithm, the localization accuracy and coverage of the proposed algorithm are respectively increased by 21.62% and 4.87%.