Disclosed is an OLED thin film packaging structure, including: a TFT substrate, an OLED, a first barrier layer, a first buffer layer, and a second barrier layer. The OLED is disposed on the TFT substrate. The first barrier layer is disposed on four sides and an upper surface of the OLED. The first buffer layer is disposed on an upper surface of the first barrier layer, and the second barrier layer covers the first barrier layer and the first buffer layer. An OLED thin film packaging method includes steps of: preparing a first barrier layer and a first buffer layer by using a first mask, and preparing a second barrier layer by using a second mask, thereby reducing a quantity of times for changing a mask, reducing a quantity of particles, and improving a thin film packaging effect.