A permanent-magnet synchronous motor of a draining pump is disclosed. It includes a permanent-magnet rotor for driving an impeller to rotate, a pump body for supporting the permanent-magnet rotor, a stator core and a stator coil. Among which, the stator coil is constructed with an enamelled aluminum wire winding which is coiled by an enamelled aluminum wire and sealed in a container. The invention applies the enamelled aluminum wire to the permanent-magnet synchronous motor of a draining pump. The winding of the stator coil and a welding part of its lead-out wire are sealed with plastic or epoxy resin which effectively isolate them from outside air, especially damp air. Therefore, the invention prevent the enamelled aluminum wire winding of the stator coil and the welding part of its lead-out wire from being oxidized in air and being corroded by the moisture, acid or alkaline matter in damp air.