The broadband yellow-orange laser is an important fluorescent source in the fields of biomedicine. Based on broadband quasi-phase matching technology of periodically polarized lithium niobate (MgO∶PPLN) crystal, a modeling scheme based on apodization step chirped MgO∶PPLN is proposed. In the chirped MgO∶PPLN, broadband sum frequency of C-band (1525-1565 nm) and 980nm laser is realized. The genetic algorithm is used to optimize the tracking rate and the increment of chirp period range. The spectral output with conversion efficiency of -11 dB, band top fluctuation of 0.047 dB and band width of 6 nm is obtained near the wavelength of 600 nm. This work provides a broadband yellow-orange all-solid-state laser output design with high conversion efficiency and low band top ripple.