Microlens array plays an important role in the field of modern optics. It is of practical significance to evaluate the quality of array devices by measuring residual stress and guiding the optimization of manufacturing process. Most of the existing measurement studies focus on the stress measurement of the whole array device, but the stress distribution of the microlens unit has not been systematically measured. Based on the principle of birefringence, this paper uses photoelastic system/ polarizing microscope respectively to measure and study microlens array devices with different base thickness ( 0. 5 mm/ 1 mm), different unit arrangement ( tangent arrangement / tight arrangement) and different microlens unit calibers (126 μm/ 1 mm) at macro / micro scale. The stress distribution law of the whole device ( macroscopic) and the stress distribution of the lens unit ( microscopic) are compared and summarized. The experimental results show that the residual stress distribution of the microlens array is uniform, and there is a significant convergence between the macro residual stress distribution and the micro residual stress. Under the premise of the same thickness, the distribution of residual stress is less affected by the arrangement and aperture size. When the thickness of the array decreases from 1 mm to 0. 5 mm, the residual stress in the same area of the square aperture microlens array increases by about 250%. For the thickness of the circular aperture microlens array, the residual stress increases by about 150% in the same measuring area. The residual stress increases significantly within the same aperture / configuration / region, decreases from 1 mm to 0. 5 mm, the residual stress in the same observation area increases by about 150%.