Fly-ash cenospheres have a hollow-ball structure,which can improve the performance of composites and reduce the amount of resin when using as filler in resin-based composites,and promote the high value-added utilization of fly-ash waste.The effects of fly-ash cenospheres with different particle sizes on the density,mechanical properties and friction and wear properties of the composites were studied.The results show that with the decrease of the particle size of fly-ash cenospheres,the density of composites decreases first and then increases,the hardness and impact strength increase first and then decrease.When the particle size of fly-ash cenospheres is 120 mesh to 140 mesh,the density of the composites is the smallest,and the cenospheres with small particle size are more conducive to reduce the density of the composites.When the particle size of fly-ash cenospheres is 80 mesh to 100 mesh,the impact strength of the composites is the largest.When filling resin-based composites with large particle size fly ash cenospheres,it is more conducive to the improvement of the high-temperature friction coefficient of the composites,and the improvement of the heat-fade resistance of theresin-based composites.The fly-ash cenospheres composites filled with particle size of 20 mesh to 40 mesh and 60 mesh to 80 mesh have good comprehensive friction and wear properties.