The present invention relates to a biocompatible nanoparticle and a use thereof and, more specifically, to a biocompatible nanoparticle formed by irradiation an electron beam to an aqueous solution comprising at least one substance selected from the group consisting of a polysaccharide, a derivative thereof and a polyethylene glycol, thereby inducing inter-molecular cross-linking or intra-molecular cross-linking, and to a use of the biocompatible nanoparticle in a drug carrier, a contrast agent, a diagnostic agent or an intestinal adhesion prevention agent or for disease prevention and treatment.