The invention provides a surgery channel device with good air-tightness, which is used for introducing a medical instrument in need of operation into a human body as a medical assistance device. The device comprises a sealing member arranged on a channel assembly so that gas leakage between a surgery channel and a human body incision can be effectively prevented through the effect of the sealing member, and the air-tightness in a surgery process is increased; and the quantity of the sealing members is increased or reduced so that the depth into the human body by the channel can be effectivelyadjusted.