The utility model discloses an insertion sealing structure for a water injection sand prevention well. The insertion sealing structure comprises an upper sealing cylinder, and a water inlet sleeve which is arranged in the upper sealing cylinder and fixedly connected with a central tube, wherein a step surface is arranged in the water inlet sleeve; a first annular space is formed between the thin-wall section of the water inlet sleeve under the step surface and the central tube; a water inlet which is communicated with the first annular space is formed on the top; a second annular space is formed between the water inlet sleeve and the cylinder wall of the upper sealing cylinder; a piston is arranged in the second annular space; a spring is clamped between the piston and the cylinder bottom of the upper sealing cylinder; the lower end of the upper sealing cylinder is connected with a lower sealing cylinder; a third annular space which is communicated with the first annular space is formed between the cylinder wall of the lower sealing cylinder and the central tube; a water outlet which is communicated with the third annular space is formed at the lower end; and a sealing module is fixed on an external circle of the lower sealing cylinder. By adoption of the structure, the central tube is not required to be lifted in the flushing process of a water injection well, and a well back-flushing process can be realized. The insertion sealing structure for the water injection sand prevention well is simple in construction process, high in efficiency, short in construction time and low in cost.