The invention discloses an insulator detection UAV and method based on an infrared thermal image and visible light, and relates to the technical field of power transmission and transformation line maintenance equipment. The insulator detection UAV comprises a UAV, a detection module, a wireless transmission module, and a ground station. The UAV is used to control the detection module to move around an insulator string in the air. The detection module includes an infrared camera and a visible light camera, and the wireless transmission module includes a sky-side wireless transceiver unit and aground-side wireless transceiver unit. The ground station is connected with the ground-side wireless transceiver unit, and includes a degradation analysis unit, a damage analysis unit and a pollutionlevel identification unit, and analyzes whether the insulator string has internal deterioration and external damages or not, and identifies the pollution level of the insulator. The UAV can realize long-distance non-contact charging detection of the internal deterioration, external damage and pollution level of the insulator string, improves the detection efficiency and accuracy, improves the safety of the testing personnel and reduces the working intensity.