An electric inboard motor for a boat, includes a main body, a motor, a motor controller, a motor mounting base, a paddle, a paddle shall, a speed-adjusting handle assembly and a main body overturning locking mechanism. The speed-adjusting handle assembly further includes a speed-adjusting handle spindle, an axle sleeve, a handle sleeve, a button, a spring and at stop block; one end of a handle shell is fixedly connected with the stop block, and the handle sleeve abuts against a stepped face of the stop block, the speed-adjusting handle spindle is connected with the handle shell in a rotation manner, the speed-adjusting handle spindle is connected with the axle sleeve through a first pin, the axle sleeve is fixedly connected with the button, and the axle sleeve is connected with the stop block in a rotation manner and connected with the handle sleeve.