In view of the stress birefringence of silicon carbide wafers, it is necessary to rotate the silicon carbide wafers with an appropriate angle along the cutting direction to highlight the position of microtubules and dislocations during real-time stress detection. However, the depth of field of the high-power microscopic inspection system is small, and when the silicon carbide wafer is tilted, the large-size wafer may not be fully within the depth of field, resulting in diffusion of focus. Virtual focus has little effect on the stress value, but it can reduce the clarity of microtubules and dislocations, and even cause smaller microtubules to disappear in the virtual focus measurement results. In order to solve this problem, this paper proposes to use the ultra depth field synthesis algorithm to merge the measured results. At the same time, a mobile platform is used to combine different measurement results to synthesize the globally focused measurement results, so as to measure the stress value. Experimental results show that this method can effectively improve the visualization effect of measurement results.