In this study, optical diffusers based on epoxy resin/thiol/nematic liquid crystal composites were prepared using different curing temperatures, curing times and curing agents (thiols). Additionally, the effects of the curing temperatures, the curing times and the thiols on the polymer ball microstructures and the optical properties of optical diffusers were investigated systematically. For applications of optical diffusers, the optimized curing temperature has been achieved by combining the high transmittance and high haze. A novel optical diffuser with ultrahigh transmittance (>94.0%), ultrahigh haze (>94.0%) and excellent diffusing ability has been obtained, of which the polymer morphology is single polymer micro-balls without aggregation.