The characteristics of a landing landmark are a key concern when an autonomous, vision-based unmanned helicopter is landing. The shape and recognition of the landmark determines the posture parameters of the unmanned helicopter and the accuracy of its autonomous landing. This article analyzes and summarizes the shapes and the detection methods of various landmarks used for autonomous landing of helicopters, as well as their relationship to the posture parameters. The characteristics of different landing landmarks are obtained, and then the development of autonomous landing landmarks is analyzed. Finally, this article offers some directions for the future research of autonomous, vision-based landing of unmanned helicopters.