The utility model discloses a speed sensor that is used for seabed crawler -type walking chassis, including land wheel and speed measuring coder, the land wheel is installed on crawler -type walking chassis and is ordered about the rotation by the seabed substrate when marcing on crawler -type walking chassis, and the input shaft of speed measuring coder links to each other with the axis of rotation of land wheel. This speed sensor have simple structure, with low costs, can the accurate measurement crawler -type advantage such as the walking actual traveling speed in chassis.