Polyethylene is the popular thermoplastic which widely used in various applications. It can be classified into several types based on density and branching. Low-density polyethylene (LDPE) consists of long branches from the main molecular chains. It is commonly used in daily life such as shopping bags, film wrap for food packaging, plastic bottles, and so on. In this study, two different melt flow rates of LDPE are fabricated as thin films prior to anneal at different temperature and time in vacuum stage. After that, the unstable of tensile properties and crystallinity of annealed films are investigated and compared with the properties of original LDPE films. With this annealed treatment, it can be found that the physical degradation is occurred and affected to the decreasing of tensile properties. In addition, the effect of applying shear force to LDPE with different time range is also studied. It is expected that the change in physical properties of the annealed LDPE and LDPE after applying with shear force will be explained. In addition, the recovery of properties will be also discussed.