Although profits of players in game cannot be accurately known in advance, such issue can be regarded as the mapping game with certain conditions and variables (time, etc.). Based on the fundamental principles of standard grey intervals, the functional zero-sum game has been established. Thereafter, it is the discussion of absolute strategies, mixed strategies, optimal strategies, and the condition of their existence. Finally, a case study of anti-piracy combat is applied to verify, modify, and validate the theory and approach proposed in this paper.