Abstract: At present, the fracture morphology of complex fracture propagation numerical simulation in unconventional reservoirs are mostly two-dimensional, and the fracturing fluid injected into the formation is regarded as pure liquid.However, the existence of proppant in the actual fracturing fluid leads to a great difference between the simulation results and the actual field results, which is difficult to be directly applied to the field optimization design.Therefore, based on the three-dimensional displacement discontinuous method and considering the flow of fracturing fluid and proppant in the wellbore and hydraulic fractures, a three-dimensional multi-cluster fracturing numerical model is established.The numerical model is solved by Newton-Raphson and the fracturing is analyzed.The influence of engineering factors such as fluid displacement, viscosity, sand ratio and cluster spacing on the growth of multiple cracks are studied.The results show that high-viscosity, high-displacement fracturing is easy to form multiple wide and short fractures, which is conducive to proppant migration to form high-diversion channels, while low-viscosity and low-displacement fracturing will form multiple narrow and long cracks affecting the proppant migration and fracturing effect.With the increase of the sand ratio, the fracture height becomes larger and the length becomes smaller.At this time, the distribution concentration of proppant in the fracture increases, and the width of the fracture in the distal fracture becomes smaller.The blocked flow of fluid and proppant in the fracture will cause sand plugging.With the increase of cluster spacing, the stress shadow effect between fractures decreases, and each fracture is more likely to expand independently.When the cluster spacing decreases, the expansion of the middle fracture is inhibited and the fracture is stable, and the seam width becomes smaller.The research results can provide theoretical guidance for the optimal design of multi-cluster fracturing in horizontal wells.