The spectrum shaping approach of chirped laser pulse is studied based on the non-colinear optical parametric chirped pulse amplification (OPCPA) with angular spectral dispersion (ASD). The effect of angular dispersion ratio on the phase mismatching of each signal frequency component, the conversion efficiency and the spectral distribution after amplification is discussed in detail. The coupled wave equations are simulated numerically when signal pulse is pumped by 532 nm with the central wavelength of 800 nm and the bandwidth of 20 nm. The results show that the bimodal spectrum with 28 nm bandwidth is obtained by use of the non-colinear OPCPA with ASD, under the optimal angular dispersion ratio. The results also indicate that the angular dispersion ratio has a considerable effect on the overall conversion efficiency and the shaped spectrum of the signal pulse after the amplification. Furthermore, the frequency-shift of signal spectrum after amplification could be modulated by adjustment of the time-delay variation between the pump and the signal pulse properly. The shaped spectrum is available to compensate the gain narrowing and spectroscopic redshift effect to some extent.