As a potential new generation display technology, OLED has many advantages such as light weight, wide visual angle, quick response, high luminous efficiency and low cost. The research and development of OLED encapsulation materials is to prevent corrosion by oxygen and moisture from the external environment and prolong the lifetime of organic emitting materials. Besides excellent barrier properties, OLED encapsulation materials also require good thermal conductivity, luminousness, mechanical strength, corrosion resistance and good adhesion to substrate and so on. In this paper, the development of OLED encapsulation materials was introduced in detail which cover the metal, glass and ceramic used for conventional encapsulation and inorganic compounds, polymers and composite materials used for the thin film encapsulation. The development direction of OLED encapsulation materials based on the demands of packaging methods in future was also discussed.