The invention provides an engine waterway plugging device which comprises a guide pipe, a handle and an end cap, wherein the guide pipe has a locking end and a connecting end, a through hole is formed in the guide pipe, and the locking end is provided with a locking mechanism used for locking an engine waterway connector; one end of the handle is located in the through hole and is in rotary connection with the connecting end; the end cap is located in the through hole and leans against one end, located in the through hole, of the handle, and the end cap is in sliding fit with the through hole; and when the handle does rotary movement, the handle drives the end cap to move towards the locking end. According to the engine waterway plugging device provided by the invention, the engine waterway connector can be inserted into the through hole of the guide pipe and is located in the locking end by the locking mechanism, and after being rotated, the handle can drive the end cap to plug the engine waterway connector so as to achieve the purpose of plugging the engine waterway connector. The engine waterway plugging device with the structure not only can be used for plugging connectors with relatively small calibers, but also cannot damage the engine waterway connector during plugging.