Abstract: The L80-13Cr heavy-wall steel tube is quenched and tempered in order to study the effect by different quench cooling speeds on the metallographic structure, hardness, strength and toughness thereof.The test results show that compared with the air-cooling process, cooling with water as the medium gets the steel tube have better hardenability, and homogeneous microstructure, and no free ferrite, and higher strength.And after subjected to treatment with the same tempering process, the average lateral impact energy at 0 ℃ of the water-quenched specimen is 47 J, and is 80%higher than that of the air-cooled specimen which is 26 J.