The effects of grain water content on the properties of sweet buckwheat and Agriophyllum squarrosum (A. squarrosum) flour prepared by cyclone pulverization were studied. The results showed that the starch content of whole buckwheat flour was significantly (P<0.05) higher than that of whole A. squarrosum flour, while the protein, fat and crude fiber contents of buckwheat flour were significantly (P<0.05) lower than that of which. The grain size, oil absorption and expansion power of two kinds of flour increased with the increase of grain water content. The water absorption and elastic modulus of whole buckwheat flour decreased significantly (P<0.05) with the increase of grain water content, but the changes of the two characteristic values of A. squarrosum flour were opposite. Grain water content had no significant effect on damaged starch content of whole buckwheat flour, but the damaged starch content of whole A. squarrosum flour decreased significantly (P<0.05) with the increase of grain water content. The values of gelatinization viscosity and gel hardness of buckwheat flour were higher than that of whole A. squarrosum flour, while the viscoelasticity and enthalpy of buckwheat flour were lower than that of whole A. squarrosum flour. The difference of damaged starch content and grain size of whole A. squarrosum flour with different water content had significant (P<0.05) effects on its expansion degree, solubility, gelatinization characteristic value, gelatinization enthalpy and dough rheological properties. These results indicated that the properties of whole A. squarrosum flour were different from buckwheat flour, and the processing properties of whole A. squarrosum flour could be controlled by changing the grain water content. This study will provide theoretical support for the high-value utilization of A. squarrosum seeds as a new food resource and help ensure national food security.