In this paper, the photoinitiator 184 and prepolymer TMPTA are microencapsulated based on the interfacial polymerization technique. The shape of microcapsules is uniform and the peak diameter is about 0.3 μm detected with scanning electron microscope (SEM) and laser particle diameter analyzer. The weight loss result verifies that the microcapsules is high thermal stable with decompose temperature above 350 ℃. The photo-harden process is investigated by the absorption spectrum and infrared (IR) technique. The absorption peak is at the wavelength of 310 nm with half width about 30nm. After exposure, the remarkable reduction in absorption intensities are observed at 1620 cm-1 for the C=C stretching and the 920.1 cm-1, 837 cm-1 for the C-H stretching on the C=C molecular bond. Such a result can be ascribed that the photo-harden reaction in the microcapsule is the process of cleavage of double bond and formation of network structure. Based on the image density property under different exposure time conditions, it can be concluded that the optimal exposure time of the microcapsule material is 20 s.