In this paper, a sliding mode controller is presented for the trajectory tracking by a group of ships with an established formation along a given parametrized path via neural network and sliding mode control technique. The control objective for each ship is to keep its relative positon in the formation while a virtual Formation Reference Point (FRP) tracks a predefined path. We first solve the virtual structure formation problems via sliding mode control method due to its excellent adaptability to external disturbance and system perturbation. Moreover, a radial basis function NN is considered in the design of the controller to approximate the unknown uncertainties efficiently. Some simulations are given to verify the theoretical results in this paper.