The invention discloses a multi-stage operating speed adjusting device and method under an automatic cutting mode of a coal cutter. The multi-stage operating speed adjusting device comprises a coal cutter control module and a handheld-type adjusting module. The handheld-type adjusting module comprises a handheld controller, a speed input key, a liquid crystal display, an alarming module and a first indicator lamp. The coal cutter control module comprises a coal cutter controller, a second wireless receiving and transmitting module and a storage. The input end of the coal cutter controller is connected with a speed detecting module, a traveling direction detecting module, a position detecting module and a speed threshold value input key module, and the output end of the coal cutter controller is connected with a coal cutter traveling motor and a second indicator lamp. The multi-stage operating speed adjusting method comprises the following steps of 1, detection for the current positionof the coal cutter; 2, judgment on the current position of the coal cutter and adjustment for the operating speed of the coal cutter; and 3, real-time detection and transmission for the operating speed of the coal cutter. According to the multi-stage operating speed adjusting device and method, design is reasonable, the operating speed of the coal cutter under the automatic cutting mode can be adjusted, optimal speed control over automatic coal cutting is achieved, and the practicability is high.