In order to study the effect of ultrafine grinding time on the quality characteristics of whole wheat flour and dough, wheat was used as raw material and the whole grain wheat was ultra-finely ground by direct grinding method. The effects of particle size on the gelatinization characteristics, thermomechanical properties of whole wheat flour rheological properties of dough, color and texture of dough were investigated. The results showed that with the increase of crushing time, the particle size of whole wheat flour decreased, and the D50 decreased from 107.20 um to 45.65 um. The particle size distribution was more concentrated. The peak viscosity decreased, and the setback value decreased from 623.33 mPa·s to 485.33 mPa·s. The reduction of particle size could delay the aging of dough and product. The hardness of dough gradually decreased with the decrease of particle size, and the elasticity and cohesion gradually increased. The water absorption rate of dough increased from 65.7% to 76.7%, and the stabilization time also showed an upward trend. The low-temperature ultrafine grinding technology of wheat grains can improve the quality of whole wheat flour, and it is feasible to apply this technology to the field of whole grain processing.