The work aims to solve the problem of quality degradation of storage and transportation equipment due to protective packing defects. Environmental impact factors were analyzed to develop a composite material consisting of surface, high-barrier layer and heat-seal layer and featuring in puncture resistance, slitting resistance, high barrier and electrostatic prevention. Performance test was performed by referring to relevant national standards. The material was utilized to design structural composition, connection status, sealing method and internal environment control mode in a scientific manner. A kind of modular combined flexible envelope which can be adapted to quantity and volume of interior equipment was developed with the composite material. An internal environment humidity control and vacuum keeping method by combining desiccant and deoxidant into a sealing agent was proposed. The computational method of desiccant and deoxidizer in sealing agent was given. The envelope can be used to provide effective protection regarding environmental factors for interior storage and transportation equipment with convenient unfolding and storage, adjustable size, and no less than 3 years of field-environment protection, which provides a new method for equipment storage protection.