Abstract: Experimental and theoretical studies on the flow characteristics of semicircular impinging stream drying were made. The variations of the particle’s velocity,the residence time along particle’s track,and the system pressure drop versus mass flowrates were determined by experiment. The particle dynamic model was developed. Under various conditions, the particle’s velocity, residence time, maximum penetration depth and the maximum penetration time, as well as the effects of various factors on fluid dynamic characteristics were calculated and discussed.　The calculatied results agree well with the experimental data. The results indicate that impinging region is the favorable field of enhancement semicircular impinging stream drying, increasing circular diameter properly is the efficient way of enhancement semicircular impinging stream drying,and reasonable gas velocity should be used to reduce the energy consumption and the operating cost.