China is the largest country for kelp cultivation. Nowadays, harvesting of kelp mainly relies on manual working, which, for its high harbor density and low efficiency, has became one of the key bottlenecks in the development of kelp industry. There is an imperative to develop kelp harvesting technology as the increasing of labor costs and a shortage of labor for the hard fieldwork. In this paper, the research and development status of the mechanized harvesting devices for raft-cultivation of kelp was reviewed and analyzed. Based on the introduction of the mode of raft-cultivation and manual harvesting of kelp, the different characteristics of kelp harvesting devices were investigated; the functions and properties of those key modules such as locomotion, kelp rope catching and separating, transmission and processing and so on were summarized; the significant impact of the model of kelp cultivation on the structure and design of the kelp harvesting devices were analyzed; the  comprehensive consideration of kelp’s special characteristics, growing environment, the particularity of cultivation mode for the research and development of kelp harvesting devices which are suitable for China’s national conditions was proposed; and several issues that should be paid attention to in the development of kelp harvesting devices were discussed.