The invention provides a satellite-borne laser near-coast terrain detection laser radar and a detection method. The satellite-borne laser near-coast terrain detection laser radar comprises a laser, atransmitting optical light splitting device, a large-aperture telescope, a relay optical device, a multi-channel photoelectric detector, a laser controller, a signal acquisition and processing module,a signal conditioning and detector control module and a comprehensive controller. Parallel dual-wavelength laser emission is utilized, large dynamic detection of deep sea and shallow sea seabed echoes is achieved through large and small view field detection of 532 nm wavelength laser echoes, synchronous detection of the sea surface is achieved through 1064 nm echo detection, and therefore the near-coast seabed terrain and a water depth are accurately measured; atmospheric detection is realized through parallel dual-wavelength laser emission and polarization receiving detection; and through multi-beam laser emission and sub-view-field receiving detection, high-efficiency measurement of an ocean wave height and the near-coast land terrain is achieved, the laser radar is carried by a satellite platform, and global-scale near-coast terrain and water depth measurement can be achieved through continuous scanning in a satellite flight direction.