A continuous depth selectivity is examined by changing the state of polarization of the signal light, based on the orthogonal polarization spectral (OPS) microcirculation imaging system. Unlike the traditional OPS system, which could only rend a two dimensional image of a certain cross-section, the elliptically polarized light controlled by the polarizer unit and the analyzer unit could do the microscopy refocusing without mechanically scanning the sample, as a result, the tissue information at different depths could be obtained. Because the proposed system matches the emission spectrum of the light source with the absorption spectrum of the erythrocyte, it has relatively high signal-to-noise ratio, and could be used to detect microcirculation. Imaging of a pork fat with a target is acquired, and the quantitative relationship between image contrast and the state of polarization is illustrated. The results show that from linearly to circularly polarized illumination, the image contrast gradually increases, and the maximum visible depth also increases. Finally, the auricle vessel of a nude mouse was detected by this polarization-controlled spectral imaging system. Through the experiment the feasibility of depth selectivity was proved. The proposed method provides new insights to microscopy refocusing of microcirculation.