Aiming at the problem of large range focus in micro-vision system, a new focus search strategy was proposed. The improved SUSAN operator and wavelet transform operator were combined as a new focus evaluation function, which has the advantages of single peak and steep peak on both sides of the peak that was divided into a quick search of the flat area and Gaussian fitting steep zone. The effectiveness of the search strategy was verified based on the self-developed micro-vision system. Then, the motor was driven directly to reach the focal plane according to the fitting results. The experimental results show that the new focus search strategy has better effect on the aspects of the real time and accuracy.