Trocar is for single-use and can avoid cross- infective. For 10mm Trocar, there is a protecting sheath at head and a compressed spring at end which can make the protecting sheath elastic. Futhermore, there is a tag by which the doctor can understand the elasticing condition of the protecting sheath when operating. At last, only 2.5mm of knifepoint will come out and on edge on the side of the knife when punctu-ringlt is very effective to protect viscera and avoid injuring so as to guarantee the safety of operation. The integrated design of Trocar Sheath has perfect airproof ability and decrease the chance of leakage. There is an additional connector for injecting CO2.It is very convenient and easy for using. Trocar Sheath has skidproof grooves. This special design make the sheath body smaller so that the wou-nd will be smaller. There are two holes for threading at the handles of trocar sheath. Trocar will be more steady when operating.