Hardness （HRB） and wear resistance as well as microstructure under different conditions were investigated on as-cast, solid solution and solid solution +aging centrifugal casting particle reinforced Al-20Si-5Mg composites cylinder liner, which were also comparatively analyzed with those of cast iron cylinder liner for automobile and motorcycle. The results show that average hardness of particle reinforced Al-20Si-5Mg composites cylinder liner is lower than that of cast iron ones. However, with increasing in loading, under dry sliding condition, wear resistance of the composites cylinder liner at as-cast, solid solution and solid solution +aging state is apparently superior to that of cast iron ones, while under wet condition, with high loading, such as 300N and 400N, it is slightly better than that of cast iron ones.