As the latest development direction of the board-level optical interconnection, the flexible electro-optical printed circuit board (FEOPCB) not only has the great advantages of the optical interconnection, but also has the characteristics of the flexible printed circuit board. Which can realize the flexible interconnection between the different subsystems, and meet the development tread of lightweight, compact and high performance for the high speed electronic system. The domestic and oversea research state of FEOPCB is introduced and analyzed in detail. The key technologies and the future research directions of the flexible interconnection circuit are discussed.