A gate valve with secure sealing mechanism, comprising: a main body, provided with a first end and a second end, with the second end having a valve opening; a driver, disposed on the main body; a sliding seat, slidingly disposed in the main body and transversely provided with a driving groove, the driving groove defining a non-linear driving track, the sliding seat provided with two parallel first guiding portions; a swing arm, with one end thereof connected to the driver and the other end thereof disposed in the driving groove, such that the driver drives the swing arm to circularly move along the driving track between a first position and a second position, so as to trigger the sliding seat to slide between the first end and the second end, wherein when the swing arm is at the first position and the second position, the swing arm is biased against a route direction of the sliding seat; and a valve member, disposed on the sliding seat for moving in parallel or vertical to the valve opening and provided with two second guiding portions, the valve member thus allowed to move in vertical to the valve opening for sealing the valve opening; wherein the sliding seat is at the first end when the swing arm is at the first position, and the sliding seat is at the second end when the swing arm is at the second position, whereby the valve member stably seals the valve opening, characterized in that each first guiding portion is provided with two symmetric connecting grooves, and each second guiding portion is provided with two symmetric matching grooves reversely disposed in relation to the connecting grooves for being coupled with the connecting grooves of the corresponding first guiding portion, with at least one circular rod passing through each of the connecting grooves and the matching grooves, respectively, such that each of the connecting grooves overlaps and cooperates with each of the matching grooves, respectively. a main body, provided with a first end and a second end, with the second end having a valve opening; a driver, disposed on the main body; a sliding seat, slidingly disposed in the main body and transversely provided with a driving groove, the driving groove defining a non-linear driving track, the sliding seat provided with two parallel first guiding portions; a swing arm, with one end thereof connected to the driver and the other end thereof disposed in the driving groove, such that the driver drives the swing arm to circularly move along the driving track between a first position and a second position, so as to trigger the sliding seat to slide between the first end and the second end, wherein when the swing arm is at the first position and the second position, the swing arm is biased against a route direction of the sliding seat; and a valve member, disposed on the sliding seat for moving in parallel or vertical to the valve opening and provided with two second guiding portions, the valve member thus allowed to move in vertical to the valve opening for sealing the valve opening; wherein the sliding seat is at the first end when the swing arm is at the first position, and the sliding seat is at the second end when the swing arm is at the second position, whereby the valve member stably seals the valve opening, characterized in that each first guiding portion is provided with two symmetric connecting grooves, and each second guiding portion is provided with two symmetric matching grooves reversely disposed in relation to the connecting grooves for being coupled with the connecting grooves of the corresponding first guiding portion, with at least one circular rod passing through each of the connecting grooves and the matching grooves, respectively, such that each of the connecting grooves overlaps and cooperates with each of the matching grooves, respectively.