The present invention relates to a semi-permanent vehicle coupler for a light rail, which comprises a buffer end and a buffer-free end. The buffer end comprises a buffer, a joint bearing connected with the buffer and a mounting seat, wherein the joint bearing is connected with the mounting seat through a coupler yoke key; the buffer-free end comprises a left pull ring, a joint bearing connected with the left pull ring and a mounting seat, wherein the joint bearing is connected with the mounting seat through a coupler yoke key; the buffer is a double-acting buffer and comprises a shell, a left end cover, a right pull ring, elastic bodies, a central shaft and a middle partition plate, wherein the central shaft passes through the centers of the left end cover and the right pull ring and is glidingly contacted with the left end cover and the right pull ring, one end of the central shaft extends out of the left end cover, the middle partition plate is fixedly arranged on the central shaft and divides the inner part of the shell into two elastic body accommodating cavities, and the elastic bodies are positioned in the two elastic body accommodating cavities; and the other end of the left pull ring is provided with a lug boss, one end of the central shaft extending out of the left end cover is also provided with a lug boss, and the two lug bosses are connected through a connecting ring.