The electronics system in a remote sensing camera will generate V/Q nonlinearity and DN/V nonlinearity in signal conversion processing and both of them effect the Modulation Transform Function(MTF) of the sub-imaging system. This paper focuses on the generation mechanism of two kinds of electronic nonlinearities and the effects of the nonlinearities on the MTF and proposes a discriminant method for the electronic nonlinearities. On the basis of the generation mechanism, the V/Q and DN/V nonlinearity theoretical models are established, their effects on the MTF of the camera are researched and a simulation experiment is performed. Experimentl results show that the MTF falls with electronic nonlinearity from 0.55 under a normal state to 0.47, and it also changes with illumination. Finally, a method based on combination of a video response curve and a Photo-response Non-uniformity (PRNU) noise curve is proposed to distinguish the V/Q nonlinearity and DN/V nonlinearity. The simulation is put forward and the feasibility of the proposed method is verified。 The research provides strong supports for the design, improvement and nonlinearity compensation of remote sensing cameras.