By using the general theory of multimode squeezed states, the difference squeezing of generalized nonlinear unequal - power higher - power in the multimode Schrodinger -cat state entangled light field is studied in detail. This light field is formed by linear superposition from three quantum states, i.e. multimode complex conjugation coherent state, multimode complex conjugation imaginary coherent state and multimode vacuum state. The conclusion shows that 1) the difference squeezing of the cat state entangled light field is independent of the vacuum state; 2) when certain conditions are satisfied, the two quadrature phases of this cat state entangled light field present unequal - power higher - power difference squeezing properties respectively, and under some other conditions, the difference squeezing effects of two quadrature phases can be displayed at the same time. The former is in conformity with the uncertainty principle. But the later is not, and is called "two-sides difference squeezing" considering the application of squeezed light in the light communication.