Abstract: In the field of engineering, the problem of pipeline blockage often exists in the process of hydrate exploitation and natural gas transportation. In order to effectively solve the blockage in the process of natural gas transportation and provide an important theoretical basis and a reference for efficient storage and transportation of oil and gas, two kinds of porous media quartz sand with different particle sizes are used to carry out the experiment of hydrate formation at the initial pressure of 8 MPa and temperature of 16 ℃ in this study. After the first formation, the constant pressure and temperature rise method are used for the hydrate decomposed with different pressure and the decomposition reaction is carried out for 150 min, then stabilized to the same initial condition as the primary formation and the secondary formation experiment is carried out. Through the curve of temperature and pressure in the reactor during hydrate formation, the influence of different primary decomposition pressure on secondary formation process and characteristic index is analyzed. The experimental results show that the secondary formation has a significant and stable memory effect compared with the primary formation. It is concluded that the effect of primary decomposition pressure on the secondary formation of hydrate is a critical pressure. When the decomposition pressure is the critical pressure, the secondary formation rate of hydrate is relatively small and the saturation is low, and the memory effect is the weakest. The results of this study are expected to provide an important support for the solution of pipeline blockage caused by the secondary formation of hydrate in the natural environment and the efficient storage and transportation of oil and gas.