A spectral focusing coherent anti-Stokes Raman scattering (CARS) microimaging system was developed using a femtosecond oscillator as the excitation source. Pump light and Stokes light were obtained by using dichromatic mirrors. Two- and three-dimensional microscopic imaging studies of the spectral focusing CARS imaging in the low-fingerprint region of polystyrene samples were carried out. While changing the delay time of pump-Stokes during two-dimensional imaging, CARS signal intensity spectra that varied with delay time were obtained. The switching of excited Raman vibrations in the process of changing the pump-Stokes delay time was analyzed by comparing it to the polystyrene Raman spectra. Furthermore, the three-dimensional CARS imaging was realized by tomography in the fixed Raman vibration mode for polystyrene samples.