In this article, the crosstalk characteristics of the few-mode optical parametric amplification (FMOPA) are studied, and the intra-mode and inter-mode four-wave mixing and their phase matching conditions in the few-mode fiber are described in detail. The time-independent nonlinear Schrodinger transmission equation in few-mode fibers is given, and the intermodal crosstalk of FMOPA is described by numerical solution method, and the corresponding semi-analytical solution is deduced. First, a new fiber structure is designed to transmit five modes in C-band (1530?1565 nm) with a bandwidth of 20 nm. Then, the mode field distributions of different modes are obtained with COMSOL simulation software, and the propagation constants and nonlinear coefficients between these modes are calculated with Matlab software. Finally, the maximum differential gain between different modes can be reduced to 0.7 dB over 150 m fiber length by properly adjusting the transmission power of each mode. The experimental results show that the crosstalk results obtained by the semi-analytical solution and the numerical solution method are highly consistent.