The invention discloses and relates to a cutting force automatic control main shaft reliability test device and a test method, and belongs to the technical field of mechanical test equipment and method. The problems that in the prior art, the real work conditions of a main shaft cannot be accurately and dynamically simulated; the control mode is complicated; the equipment manufacturing cost is high are solved. The main shaft reliability test device consists of a main shaft installing table, a cutting force automatic control device, a cutting torque loading device, state monitoring equipment and auxiliary equipment, wherein the cutting force automatic control device consists of a cutting force magnitude loading mechanism, a cutting force direction regulating mechanism, an electromagnetic locking mechanism and a loading device support frame. The test method of the main shaft reliability test device comprises the following steps: 1, obtaining and processing the load and state parameters; 2, performing detection and debugging on the cutting force automatic control main shaft reliability test device before the work; 3, the cutting force automatic control main shaft reliability test device simulates the work condition loading experiments.