High-quality refractive microlens and microlens array have been fabricated using drop-on-demand and in-situ thermal polymerization technology with polymer PMMA and its monomer MMA.Microlenses diameters and heights range from d=1 mm to 3 mm,and h=100 μm to 400 μm,respectively.A focal length ranges from 1mm to 4 mm approximately.All the components have high optical transparency(90%)at the wavelength of 1.55 μm to be suitable for optical communication coupled devices.The surface roughness of microlens is measured by an atomic force microscope(AFM-Ⅱ).Micro-lens forming mechanics has been analyzed by surface tension theory.