The invention relates to an augmented reality (AR) helmet with a lens retracting and releasing function for engineering design. The AR helmet comprises a main body, a camera, two lenses, a retractingand releasing mechanism and two cleaning mechanisms, wherein the retracting and releasing mechanism comprises a first driving assembly, a base, a fixed rod and two rotating assemblies, wherein each rotating assembly comprises a movable rod, a limiting block, a rotating rod, a torsion spring and a spring; each cleaning mechanism comprises a second driving assembly, a transmission assembly, a cleaning assembly, a support rod, a movable frame, two driving rods, two movable blocks, two driving blocks and two bearing seats. The AR helmet with the lens retracting and releasing function for the engineering design is provided with the retracting and releasing mechanism, so that a worker can control the retracting and releasing of the lenses according to the situation; furthermore, the distance between the two lenses can be controlled, so that the practicality of the AR helmet is improved. In addition, the cleaning mechanisms can be used for cleaning water mist and dust on the surfaces of the lenses, so that the clarity of the lenses is improved.