DOA (Direction of arrival) estimation is the primary function of split-beam fish finders. Commonly used wideband DOA estimation methods include cross-correlation, cross-power spectrum and adaptive filtering. However, when the echo overlap occurs due to small fish spacing, there are significant errors in these methods. In this paper, a method of DOA for wideband split-beam fish finder is proposed by using LFM signal pulse compression technique, and the relevant theoretical derivation is provided. This method is computationally small and easy to implement. Simulation results show that this method can provide accurate DOA estimation when the target spacing is greater than the distance resolution of the fish finder, and has good noise resistance.