Abstract: A high spatial resolution sample optical imaging system for the time of flight-secondary ion mass spectrometer （TOF-SIMS） was designed. The system consists of an improved Schwarzschild double reflection system, a reflector lens of 45°, a zoom lens and a CCD image sensor. The ZEMAX software was used to calculate and improve the initial Schwarzschild model and give the parameters of improved system. The simulation results show that the best imaging resolution of the system can reach 1 μm, the maximum resolution can achieve to 0.4 μm, and the RMS radius is less than airy disk diameter. The wave aberration can satisfy the Rayleigh judgment, and the image quality shows well.