Observation mark for surveying and mapping

The observation mark comprises a prefabricated wall body and a pre-buried mark pipe assembly, the pre-buried mark pipe assembly is fixedly installed on the inner side of the prefabricated wall body in a pre-buried mode, an anti-falling elastic rope is arranged at the exposed outer end of the pre-buried mark pipe assembly, a pre-buried pipe blanking plug is arranged at the tail end of the anti-falling elastic rope, and the pre-buried pipe blanking plug is connected with the pre-buried mark pipe assembly. The pre-buried mark pipe assembly is firstly pre-buried at the designated surveying and mapping position of the prefabricated wall body, effective fixing of the pre-buried mark pipe assembly is achieved, due to the fact that the pre-buried mark pipe assembly is hollow, the pre-buried mark pipe assembly is conveniently connected with the observation mark nail in a sleeved mode, and the observation mark nail is guaranteed not to loosen or rotate through strong magnetic connection. In this way, the observation ma