The invention discloses a target angle calibrating device and method for an infrared target simulator based on a thermal imager, and belongs to the technical field of infrared target simulator detection, and aims to provide precisely controllable and repeatable test conditions for testing and estimating performances of infrared detecting equipment. The target angle calibrating device comprises a black radiation source, a to-be-calibrated infrared target simulator, a high-precision regulating mechanism, an infrared thermal imager, a two-dimensional high-precision rotary table and a test pedestal, wherein the black radiation source is positioned on the test pedestal; after being positioned in the black radiation source, the to-be-calibrated infrared target simulator is fixedly arranged on the high-precision regulating mechanism and is as high as the black radiation source; after being positioned on the to-be-calibrated infrared target simulator, the infrared thermal imager is mounted onthe two-dimensional high-precision rotary table and is as high as optical axis of the to-be-calibrated infrared target simulator; after passing the to-be-calibrated infrared target simulator, infraredradiation emitted by the black radiation source forms parallel light to emit, so that infrared wave sections are generated; and light passes through the infrared thermal imager for measuring a targetpoint generated by the to-be-calibrated infrared target simulator.