The utility model relates to a part of a device for extracting and draining gas in coal mine, in particular to an angle-adjustable PE elbow connection device for extracting gas in coal mine. The angle-adjustable PE elbow connection device solves the problem that the joint in the prior gas extraction drainage device can not suits multiple positions on site. The angle-adjustable PE elbow connectiondevice comprises an upper elbow and a lower elbow, wherein the upper elbow is socket-connected with the lower elbow; an anti-loosing screw is connected between the upper elbow and the lower elbow; fastening screw caps with the internal thread are respectively sheathed on the outer ports of the upper elbow and the lower elbow; a clamping sleeve is arranged in the thread-free segment of the fastening screw caps; and a seal ring and a clamp ring are arranged between the clamping sleeve and the ports. The structure of the angle-adjustable PE elbow connection device results in lighter weight, whichfacilitates transportation and installation. By adopting the composite bidirectional design of the upper elbow and the lower elbow, the connection part not only can be sealed under the negative pressure, but also can be rotated by any angles at will.