The helicopter is a crucial tool of marine search,and its searching ability needs to be improved with the increase of national marine trade and military activities. The rationality of the search route is the key to an efficient search and a high success rate. Under the premise of the access to the target location,this paper provides the route-planning methods under different scenarios. At first,two kinds of electronic route-planning methods are given under the scenario of using handheld device. Then,the route-planning method for visual search is analyzed emphatically,with the range of visual observation,the estimation of survival time,the limits on flight height,the limits on flight speed,the calculation of marine search width,the calculation of the starting point of searching,and the selecting principle and parameter settings of the three common routes. At last,the flow chart of the whole algorithm is presented with the simulation analysis.