In this work, self-lubricating functional microcapsules (MCLMs) containing methyl silicone oil as core materials, were prepared with poly (melamine-formaldehyde) (PMF) as shell material by in-situ polymerization method and the MCLMs/polystyrene (PS) composites were synthesized through bulk polymerization method using styrene (St) as monomer, azodiisobutyronitrile (AIBN) as initiator and MCLMs as functional filler. And the morphology and mechanical properties of MCLMs were observed by SEM, TEM and nano-indenter. They were further adopted as filler to improve the tribological properties of polystyrene composites and the tribological behaviors of the polystyrene composites filled with MCLMs were investigated by block-on-ring wear tester. The mechanical properties and thermal stability of the composites were evaluated by microcomputer control electronic universal testing machine and TGA. The results show that the friction coefficient of MCLMs/PS composites is 0.22 and wear rate decreases 92% under100 N, 50 r/min, when the mass fraction of MCLMs added is 15%; meanwhile, toughening effect of MCLMs is remarkable.