The main characteristics of lamella reticulated shells are introduced in this paper. According to an engineering example of lamella reticulated shells, the principle of strengthening is indicated for reticulated shells. Based on the results of structural calculation, the main problem is gained for the long-span reticulated shells. Carbon fiber sheet strengthening method is a perfect strengthening method for reticulated shells as comparied with other strengthening methods. So the method could offer experience for the similar strengthening projects.