The formation behaviors of methane hydrate in the sea mud from South China Sea were studied.The sea mud with mean pore diameter of 12.178 nm and total pore volume of 4.997 ×10 -2 ml /g,surface area of 16.412 m2 /g was used for the experiments.The mass fraction of water in the sea mud is 40%.The experiments were carried out at the temperature range of 274.15 -281.15 K and the initial formation pressure range of 10.2-14.4 MPa.The experiment results show that the formation rate of methane hydrate in the sea mud and the gas consumption increase with the increase of initial formation pressure and increase with the decrease of tempera-ture.The complex pore structure of the sea mud can promote the nucleation of the hydrate,but reduce the final conversion of the water,and this effect will be strengthened with the increase of the temperature and the de-crease of the initial formation pressure.