Abstract: The 27SiMn seamless steel tube is currently used for the purpose of coal-mining-used hydraulic prop and support for other mines in the country. Due to the development of the coal-mining industry and the more stringent safety requirements,the mechanical properties of such tubes as obtained from heat treatment in massive production process are no longer satisfactory to the end-user’ s requirement for high strength and high toughness. A kind of seamless steel tube with high strength & toughness for hydraulic prop service has been successfully developed,and massive production thereof has been started. The feedbacks from the end-users show that the high strength,toughness and weldability of the tube have been in compliance with their requirements.