A flexible encapsulating material, a method for preparing the flexible encapsulating material, and an encapsulating method using the flexible encapsulating material are provided. The flexible encapsulating material includes an epoxy resin represented by a Formula (1), a curing agent, and a curing accelerator and optionally includes a coupling agent, wherein based on 100 parts by weight of a total usage amount of the epoxy resin (A), the curing agent (B), and the curing accelerator (C), a usage amount of the epoxy resin (A) is 85 parts by weight or more, and based on 100 parts by weight of the usage amount of the epoxy resin (A), a usage amount of the coupling agent (D) is 0 to 5 parts by weight.