The utility model discloses a sand distribution device for preparing sand samples with different compactness in an indoor model test. The sand distribution device comprises a sand falling tank and a trolley platform; a sand leakage plate with uniformly distributed round holes is arranged at the bottom of the sand falling tank; two sand baffles are arranged under the sand leakage plate; the trolley platform can reciprocate along guide rails arranged on the sand falling tank; the trolley platform is provided with an opening and closing mechanism for opening and closing the sand baffles of the sand falling tank; a control rod of the opening and closing mechanism is mounted on a trolley platform plate by a spring bottom plate, a pressure spring and a fastener from bottom to top; the trolley platform plate is provided with an anti-rotation key for the control rod; and a check block for opening and closing the sand baffles of the sand falling tank is arranged at the lower end of the control rod. Anti-rebounding stop pins for preventing the sand baffles from being rebounded during falling are respectively arranged outside sand falling tank bracket legs. The device overcomes the defects of a manual tamping method in the conventional sand sample preparation process, is labor-saving and time-saving, is convenient and rapid and can be used for conveniently and rapidly preparing the sand samples with different compactness in the geotechnical engineering indoor model test so as to implement accurate control on physical characteristics of a sand bed of test sand and lay the important foundation for accuracy and reliability of data of the model test.