In order to evaluate the effect of the soaking process on the applied qualities of rice power， the water absorption and protein and microelement and granularity and damage and microstructure etc of brown rice and rice were evaluated in different soaking time of 0.25， 0.5， 0.75， 1， 2， 3， 4， 5， 6， 7， 8 h. The results showed that the water absorption rate of white rice and brown rice increased rapidly within 1 h and 2 h respectively， and the water absorption rate of brown rice was significantly lower than that of white rice， and the water absorption rate was significantly lower than that of white rice within 2 h. After 2 h， the water absorption rate of brown rice increases slowly， and tends to be stable at 5 h. With the extension of soaking time， more honeycomb structures appeared on the surface of white rice， and the honeycomb became larger. The separation appeared between cell walls， and the structure between starch granules became loose， the contents of protein， manganese， zinc and potassium all showed a decreasing trend. The structure of brown rice did not change obviously with time. The granularity of white rice flour within 0.75 h and brown rice flour within 4 h decreases continuously. The starch loss content of white rice flour decreased with the increase of soaking time， but there was no significant change in brown rice flour. In short， because the outer layer of brown rice was wrapped by the peel， it took a long time for water to enter into the brown rice. The water absorption characteristic of brown rice was slower than white rice. With the extension of soaking time， the structure and nutrition of white rice changed significantly， but that of brown rice flour was not obvious.