The physical properties of rice husk ash burnt at 800 ๐c, was analyzed by XRF. The results showed the composition of untreated rice husk, treated rice husk with 0.4M hydrochloric acid, consisted of SiO2 92.880, 98.070 percent respectively. According to the study of mechanical properties founded that: the maximum force of natural rubber, natural rubber mixed with untreated rice husk, natural rubber mixed with treated rice husk with 0.4M hydrochloric acid were 25.582 , 28.886 and 35.040 N respectively. The percentage of strain at the maximum load were 67.175 , 67.954 and 74.002 respectively.