Four 6061 aluminum systems were prepared, including the cast 6061 alloy processed by TMT or ECAP, the PM 6061 alloy, and the modified PM 6061 alloy added with 1 vol% nano-SiO2. The modified 6061/1%nano-SiO2 alloy possessed a grain size similar to0.5 mum and maintained fine grain size upon loading at high temperatures, resulting in HSRS over 300% at 550-590 degreesC and 1-5x10(-1) s(-1). The grain boundary misorientation distribution in the modified 6061/1%nano-SiO2 alloy was also most random compared with other three unmodified 6061 alloys. The current results suggest that the addition of a small amount (1 vol%) of cheaper SiO2 or Al2O3 nano-particles into commercial Al alloys can effectively suppress grain growth at high temperatures and enhance HSRS, similar to the effects by adding 15-25 vol% micro-sized SiC or Si3N4 reinforcing particulates or whiskers.