The planning of secure covert paths in marine environments is a challenging task. In response to the task requirements of spacecraft for secure covert paths and the planning limitations in high-dimensional and complex marine environments, this paper proposes a secure covert path planning algorithm based on the improved DQN+D-S simplified state-space algorithm. The algorithm comprehensively processes various element information in the marine environment, converts it into situational values, and divides it into ten levels. A safe covert path planning model suitable for the marine environment was established by evaluating the situation in different regions. Through continuous learning, algorithms can obtain more accurate value functions and strategies, thereby achieving better path planning results. Finally, the effectiveness of this method was verified through a large number of simulation experiments. The experimental results show that this method can find safe and covert paths for spacecraft in marine environments, and it exhibits high efficiency and superior performance in path time consumption and safety evaluation.