Abstract: Hydraulic fracturing is a kind of most commonly used well stimulation technology. Under the same formation conditions and same fracture dimensions, the amount and distribution of proppant in fractures will change the flow conductivity of fractures and impact well production. At present, there are few researches on proppant distribution and flow in fractures during flowback after fracturing. The paper analyzes the influences of various factors on proppant amount in fractures through proppant flow simulation in fractures with the software COMSOL. The simulation result shows that the most important factor influencing proppant retention is the flow rate of fracturing flowback fluid and the viscosity of fracturing fluid after gel breaking and the adjustment of flowback parameter can inhibit the backflow of proppant. It is suggested that during fracturing the flowback fluid viscosity should be kept below 20 mPa·s and the fracturing fluid flow rate at 240 m3/d