An optical film, a manufacturing method thereof and a display device are provided. The optical film includes a photonic crystal film substrate and a plurality of linear defective portions penetrating the photonic crystal film substrate in a thickness direction in the photonic crystal film substrate. A lattice period of each of the linear defective portions is different from a lattice period of the photonic crystal film substrate, and the photonic crystal film substrate includes a plurality of first regions and a plurality of second regions. The first regions and the second regions are alternately distributed along at least one direction in a plane where the photonic crystal thin film is located. The linear defective portion located in each of the first regions has a first light exiting direction. The linear defective portion in each of the second regions has a second light exiting direction.