In order to improve the locating accuracy in Wireless Senor Network (WSN) node localization, an algorithm based on Particle Swarm Optimization (PSO) and Shuffled Frog Leaping Algorithm (SFLA) was proposed, namely Bi-system Cooperative Optimization (BCO) algorithm. With the advantages of fast convergence in PSO and high optimization precision in SFLA, the proposed algorithm was easier to converge through less iterations and achieve higher accuracy of depth search. The simulation experiments indicate that the BCO algorithm is effective. First, the BCO algorithm can be very close to the optimal solution when it is used for solving the test target functions with better locating accuracy and higher convergence speed. Meanwhile, when the proposed algorithm is used for node localization based on Received Signal Strength Indicator (RSSI), the absolute distance error of the prediction location and the actual location is less than 0.05 meters. Compared with the Improved Particle Swarm Optimization algorithm based on RSSI (IPSO-RSSI), the locating accuracy of the proposed algorithm can be increased 10 times at least.