Disclosed is a flexible composite material capable of shielding nuclear radiation. The flexible composite material mainly comprises lead fiber cloth, nuclear-radiation resistant powder and high-polymer material. The lead fiber cloth and the nuclear-radiation resistant powder can be reinforcing materials of composite and nuclear-radiation resistant function materials. The base material is the high-polymer material and has a certain function of nuclear radiation resistance. The flexible composite material is prepared by steps: A, the lead fiber cloth is treated by coupling agent in advance so as to reduce surface tension, and compatibility of the high-polymer material is improved; B, the nuclear-radiation resistant powder is uniformly mixed with the coupling agent firstly and is dispersed into the high-polymer material through high-speed stirring; and C, the lead fiber cloth treated and the high-polymer material dispersed with the nuclear radiation resistant powder are manufactured into a lead fiber based high-polymer composite material through composite forming, demoulding and maintaining. The flexible composite material capable of shielding nuclear radiation has the advantages of excellent nuclear radiation resistance, good mechanical performance, stability and flexibility, foldability, bendability, light weight and low cost and can be widely applied to protection of the field of nuclear radiation.