The invention relates to a quick-plugging waterproof circular electric connector. The quick-plugging waterproof circular electric connector comprises a socket, a plug and a clamping device; the clamping device is used for connecting the plug onto the socket in a pluggable manner; the clamping device comprises protruding clamping blocks and annular clamping buckles, wherein the protruding clamping blocks are connected onto the socket, and the annular clamping buckles are connected onto the plug, or the protruding clamping blocks are connected onto the plug, and the annular clamping buckles are connected onto the socket; when the plug is plugged into the socket, the protruding clamping block fold the annular clamping buckles, so that the plug can be allowed to enter the socket; when the plug completely enters the socket, the annular clamping buckles are unfolded and clamped onto the upper end surfaces of the protruding clamping blocks, so that relative displacement of the plug and socket along the axial direction of the electric connector can be limited; and when the plug is pulled out from the socket, the annular clamping buckles are folded, so that the plug can be allowed to move out from the socket. The electric connector has the advantages of convenient and rapid plugging, long service life and simple and reasonable structure.