Abstract: The marine flexible composite pipes are quite suitable for the development of deepwater oil and gas reservoirsdue to the excellent characteristics of design abilities, economics and dynamic behaviors. In this paper, the domestic andforeign research results on gas permeation and condensation were reviewed based on the special multilayer compositestructure of flexible pipe. And safety hazard, heat and mass transfer mechanism, prediction model, annulus condensation, gas and liquid migration and corrosion failure were mainly discussed. Finally, in view of that the prediction accuracy ofthe permeation rate is low and the condensate form in annulus is undefined when existing research results are appliedto deepwater conditions, it was proposed to focus on the following three aspects in the future researches, i.e., the gaspermeating and condensing model of the multi-field heat and mass couplings in the flow-solid-mass-seawater system, theprediction of the condensation process and distribution characteristics of local water vapor in annulus and the corrosionfatiguecoupling behavior in metal components, and the annulus gas monitoring, control system optimization and reliabilityevaluation.