High polymer materials such as rubber, plastic and fiber will have a certain shrinkage under a certain temperature. Most products are required to have a good thermal stability and small shrinkage, but some products are required to have a large shrinkage when heated. The performance that high polymer materials will shrink by heating is opposite to that of metal materials. Taking advantage of this performance, we make the high polymer materials into heat-shrinkable rubber boot, heat-shrinkable membrane plastic, heat-shrinkable fiber and fiber-knitting which will be used for packaging.