Membrane structure is a new-type space constructional structure with certain space shapes as the covering structure formed by some pre-tensioned stress generated from within the combination of multiple high-level membranes(PVC or TEFLON) and tension members(steel frames,bars or ropes) in a certain way to bear a certain degree of imposed load.It features light weight, big span and short construction cycle. It is convenient for factory production,processing and installation. It is cost-effective and characterized by translucence,self-cleansing function and fire-retardance,Known as the fifth generation excellent building materials, it is applicable in sports facilities,cultural and recreational facilities,commercial announcement facilities,landmark buildings,etc. Membrane structure can be divided into inflated membrane structures and tensioned membrane structures.Indoor and outdoor presssure difference (between 10mm-30mm of water-column height in general) creates a buoyancy force on roof membranes, thus realizing a large span.Tensioned membrane structure is constructed by the support of pillars and steel frames or stretched steel ropes. Thus it has a beautiful and flexible form. Common membrane types for membrane construction engineering: There are two common types of membrane materials: One is PVC(polyester fiber fabric coated with polrvinyl chloride), whose surface is coated with a layer of fluorocarbon such as PVDF(polyvinylidene fluoride), or a layer of TEDLAR (polyvinyl fluoride)membrane. It is mainly characterized by great elasticity, rich colors, good folding resistance and good self-cleansing function. It is also easy to process and cost effective. Its service life can reach 15 years. Another is PTFE (glass fiber fabric coated with polytetrafluoroethylene). It is mainly characterized by high strength, elastic modulus, good self-cleansing and fire retarding performance. It is expensive, not easy to fold, and demanding on the precision of cutting and prccessing. With a service life of over 30 years ,it is suitable for permanent buildings.