Abstract: For conventional oil drain device, oil drain can be realized only by dropping a bar to cut off the drain pin. But in oil wells where the sucker rod is broken, oil drain cannot be realized because the bar cannot be dropped, and secondary shut-in cannot be achieved after oil drain. In view of the drawbacks of conventional oil drain devices and by making reference to the working principle of Y221 packer, a closable rotary oil drain device has been developed by conducting theoretical calculation of reversing mechanism. This tool is designed to realize oil drain function by lowering the pipe while rotating and picking up the pipe and then closing the drain hole by lowering the string. It is of novel structure, simple in operation and reliable in leakproofness. Except that it can realize oil drain without tripping out the rod string, it can realize repeated use of switch on the oil drain device, hence avoiding damaging the environment by tripping out the string with liquid. This tool was tested indoor in No. 3 Oil Production Plant in Zhongyuan Oilfield and was field tested in oil wells with pump depth of over 3 000 m. The successful rate was 100%, so it can be further promoted and applied.