In order to realize remote detection of surface cracks of cable-stayed bridges, a four lenses high definition video telephoto objective is designed. The image sensor is a complementary metal-oxide-semiconductor (CMOS) camera with a cell size of 1.4 μm×1.4 μm, target surface size of 1/2.3″ and a definition of 14 megapixel. To match the design requirement of the camera, the definition on the image surface of the telephoto objective is designed as 357 lp/mm, with a focal length of 320 mm, the relative aperture of 1/6.95, and the angle of view field of 1.379°. On the object side, the telephoto objective has the capability to distinguish a line with width of 2 mm at a distance of 228 m, which satisfies the distance and the definition requirement for the cable detection of normal cable-stayed bridges.