In one embodiment, a package of an environmental sensitive element including a flexible substrate, an environmental sensitive element and an encapsulation is provided. The environmental sensitive element is disposed on the flexible substrate. The encapsulation covers the environmental sensitive element, wherein the Young's mudulus of the encapsulation ranges from about 5 GPa to about 15 GPa, hardness of the encapsulation ranges from about 0.4 GPa to about 1.0 GPa, and water vapor transmittance rate (WVTR) of the encapsulation is less than 10−2 g/cm2 day.