Abstract: Aiming at the problem of multi-source positioning in underwater sensor network system, a multi-array based direct positioning method for shallow sea sources is proposed. In this method, the receiving model of multiple arrays is built based on the normal wave theory, and the joint likelihood cost function is established according to the received data of the multiple arrays. Then, the estimation of two dimensional multi-source positions can directly be obtained by the genetic algorithm. The simulation results show that the source positioning error of this method is smaller than the step by step positioning method, and the positioning error is stable within 50 m at higher signal-to-noise ratio. In this method, the estimation of multi-source positions can be performed by combining multiple arrays, which avoids the second estimation error in the traditional step by step positioning method, thereby to improve the source positioning accuracy.