The problem of distributed detection fusion using multiple sensors for remote underwater target detection is studied.Considering that multiple access channel (MAC) schemes are able to offer high efficiency in bandwidth usage and consume less energy than the parallel access channel (PAC),the MAC scheme is introduced into the underwater target detection field.The model of underwater distributed detection fusion based on MAC schemes is established.A new method for detection fusion of MAC based on deflection coefficient maximization (DCM) and Neyman-Pearson (NP) rule is proposed.Under the power constraint of local sensors,this paper uses the DCM theory to derive the optimal weight coefficients and offsets.The closed-form expressions of detection probability and false alarm probability for fusion systems are obtained.The optimal detection performance of fusion systems is analyzed and deeply researched.Both the theory analysis and simulation experiments indicate that the proposed method could improve the detection performance and decrease the error probability effectively under power constraints of local sensors and low signal to noise ratio.