The invention provides a nuclear fuel detection device and method. The nuclear fuel detection device comprises a detection module, a peripheral and transverse transfer module and an installation module, wherein the detection module comprises an appearance detection device and a three-dimensional monitoring device; and the appearance detection device comprises a camera assembly and a light source assembly. The invention further provides a nuclear fuel detection method. The method comprises the steps of detecting a to-be-detected part of nuclear fuel, and adjusting a light source angle and a reflector elevation angle according to an operation instruction; shooting the to-be-detected part of the nuclear fuel by the camera; displaying a specific image on a terminal by the camera after processing; adopting grating projection equipment as a light source and projecting the grating projection equipment on the nuclear fuel through a grating; and displaying an actual 3D outline image and data analysis result of the nuclear fuel on the terminal. Through the design, the nuclear fuel detection device plays a role in full-range measurement of three-dimensional geometric dimension data and deformation conditions of a fuel assembly and a fuel rod, can play an online monitoring role and is capable of providing nuclear safeguard.