An approach for wavelength tuning of Stokes optical pulse with high speed and wide range for coherent anti-Stokes Raman scattering (CARS) excitation source is presented based on the liquid crystal phase retardance. Influences of the photonic crystal fiber (PCF) length and optical pulse peak power on the frequency shift resulting from the soliton self-frequency shift (SSFS) are analyzed through the numerical simulation. Result shows that when an optical pulse with peak power 2.7 kW is launched into a 2 m PCF, the detectable wavenumber is 3509 cm-1. A fast wavelength tuning module is constructed with a liquid crystal variable retarder, and then the experiment setup is established. Experimental results show that the response time of wavelength switching can reach 0.165 ms. Tuning range of the central wavelength of the first order soliton is from 807 nm to 1064 nm when the optical pulse peak power with a range from 0.108 kW to 2.517 kW is launched into a 1.98 m PCF, and the theoretical detectable wavenumber will range from 432 cm-1 to 3422 cm-1.