In this paper, firstly according to the basic characteristics of chaos theory, we establish the nonlinear enlarge model about tent map, especially the initial-value sensitive dependence and one-to-one correspondence between chaotic orbit and the initial value. Secondly, we study the concrete characteristics with which the tent mapping system can realize nonlinear amplification. And the binary relationship between input and output is analyzed. Then we make numerical and circuit simulations of nonlinear amplification of the sine signal and the sine signal with noise. We compare the results of linear amplification and nonlinear amplification by tent mapping. At last, the advantages and disadvantages of the realized situations are discussed. The simulation results proved the superiority of the weak signal nonlinear amplification method.