An organic light emitting film package structure includes an organic light emitting unit and a film structure covering the organic light emitting unit. The film structure includes a first film as a bottom layer, a second film as a top layer, and a transition layer disposed between the first second films. The first film is SiX or SiXY, the second film is SiY or SiXY, and the transition layer includes multiple SiXnYm layers. The first and second films have different materials. A difference in atomic ratio of X or Y between two adjacent SiXnYm layers in the transition layer is greater than a difference in atomic ratio of X or Y between the first film and its adjacent SiXnYm layer or a difference in atomic ratio of X or Y between the second film and its adjacent SiXnYm. The value of m and n ranges from 0 to 1, inclusive.