The invention provides an indoor swimming machine. The indoor swimming machine comprises a base body, a spring fixing frame, a spring, a baffle, a motor, a blade, a filtering screen, an infrared transmitter, an infrared receiver, a circuit board, an MCU, a relay switch, a small screw and a big screw, wherein the base body is cuboid; a rectangular swimming room is arranged downward below the central region of the top of the base body; a head vertical slot and a tail vertical slot are respectively downward formed from the top surfaces of the head of base body and the tail; a mounting platform is arranged in the head vertical slot; a cylindrical mounting hole is formed in the mounting platform; the motor is fixed on the upper side of the interior of the mounting hole through the small screw; the spring fixing frame is mounted in a ring slot in the mounting hole; the upper end surface of the spring is welded with the bottom surface of the spring fixing frame; the oval baffle is welded with the lower end surface of the spring; the filtering screen is in a rectangular mesh shape and is laid on a check block of the tail vertical slot; the infrared transmitter and the infrared receiver are mounted in the head region of the swimming room; the MCU connects and disconnects the current of the motor through the relay switch, so that the fact that water flows from the head to the tail of the swimming room is realized.