Laser resistor trimming machine, whose precision depends on the optical performance of the scanning lens, is widely used in tuning the chip resistors. According to the practical requirements, two kinds of F-Theta lenses working in different wavelength (1 064 nm and 532 nm) are designed. The Fields of View (FOV) are ±28°and ±25°. The focusing spot diameter are about 30μm and 10μm. The final design result shows that the calibrated F-Theta distortions are both less than 0.1％ and the energy utilization rate are nearly 90％ which means that the focusing performances are close to the diffraction-limited. Both lenses can be exchanged and located conveniently on account of the simple and compact structures. The requirements of resistor trimming are satisfied well.