A method for creating a map based on 3D laser that includes: planning a route, and acquiring data in a movement process of a mobile robot; loading acquired data by using a map creating tool; performing initial alignment to adjacent laser data; performing accurate alignment to the adjacent laser data; performing closed-loop association to the same area passed through by the mobile robot, and establishing a closed-loop constraint; performing global optimization solution to an entire map for which the closed-loop constraint is established; and superposing all laser data, and outputting a laser map. The method does not depend on GPS and is not restricted by GPS signals. By using the method, cumbersome surveying and mapping operations can be avoided and large-scale maps of various indoor and outdoor environments can be created and maps can be finely adjusted off line, and high-accuracy maps can be created.