To solve the environment and health issues arose from the sulfur vulcanization, a facile and completely eco-friendly method of latex-assembly and in situ cross-linking is developed to prepare fully bio-based and high-performance rubber films. The films are featured by a "reinforced concrete" structure composed of dynamically cross-linked chitosan framework and unvulcanized deproteinized natural rubber (DPNR) matrix. The self-assembly of DPNR latex particles and chitosan, as well as the in situ cross-linking of chitosan in the film forming process are confirmed by transmission electron microscope and dynamic light scattering. As green rubbers without vulcanization, the asdesigned composite films possess excellent mechanic properties comparable to those of the sulfur vulcanized DPNR film, whose tensile strength and toughness reach 15.2 MPa and 77.6 MJ m À3 respectively. Moreover, the films exhibited appropriate permeability to moisture and achievable reprocessing, which have potential applications in wearable devices.