Based on the state superposition principle of quantum mechanics, asymmetrical multimode functional superposition state light field with the superposition of four quantum states is constructed. By using multimode squeezing state theory, this paper makes a detailed study of the unequal-power higher-power amplitude-squeezing of generalized magnetic-field of 4MFSS light field in medium and it is found that 1) under certain conditions, the generalized magnetic-field of 4MFSS light field shows periodical generalized nonlinear unequal-power higher-power amplitude-squeezing; 2) the Nj-th power higher-power amplitude-squeezing shown in the generalized magnetic-field of 4MFSS light field is obviously affected by the coefficient of the gain medium or of the absorption medium. In the gain medium, when the light field spreading distance becomes farther, the extent, range and effect of Nj-th power higher-power amplitude-squeezing are intensified; in the absorption medium, when the light field spreading distance becomes farther, the extent, range and effect of Nj-th power higher-power amplitude-squeezing are decreased.