In order to realize the anti-sea combat capability requirement generation of the new types of naval guns, the framework model is established, the anti-sea combat mission is decomposed and the capability index system of the naval gun is constructed.The mapping models are established, including the detection probability model, the maximum detection distance and tracking distance model, the single-shot hitting probability model, the reaction time model and so on.Taking the system accuracy when shooting a target at 25 km away with the given single-shot hitting probability as the standard, the simulation experiment analyzes the capability requirements to the new naval gun at different firing distances under different initial velocities. The model method can quantitatively generate the capability indicator requirements that satisfy the operational mission, and has theoretical and practical significance for scientific development of naval gun weapon equipment.