The invention discloses a PE ball valve with a discharge function, and relates to the technical field of ball valves. The PE ball valve with the discharge function at least comprises a valve seat, a valve core, a valve rod and two connecting pipes, wherein the valve core is arranged in the valve seat; the valve rod is positioned on the valve seat for driving the valve core to rotate; the two connecting pipes are separately fixed on the ports of both sides of the valve seat; at least one of the two connecting pipes is provided with a discharge mechanism; the discharge mechanism at least comprises a discharge pipe and an air outlet pipe; a sealing partition plate for sealing pipe holes of the discharge pipe is horizontally arranged in the discharge pipe; the air outlet pipe comprises a mainpipe and a branch pipe; a sleeving pipe is coaxially arranged in the main pipe; the inner wall of the sleeving pipe is smooth; the wall of the sleeving pipe is provided with a gap used for communicating with the branch pipe; and a hole opener sliding up and down along the inner wall of the sleeving pipe is arranged in the sleeving pipe. By means of the PE ball valve with the discharge function, the problem that an existing PE ball valve has to stop the natural gas transportation for communicating with a discharge device is solved, and the PE ball valve which can open the hole to communicate with the discharge device during the normal transportation of the natural gas is proposed.