An optical film with super low retardation, including metal oxide nano-particles dispersed in a transparent resin having a three-dimensional crosslinking structure. The optical film has about 0-2 nm in-plane retardation (Ro) and almost zero out-of-plane retardation (Rth). The optical film can replace conventional triacetyl cellulose (TAC) as a polarizer protective film to improve black-white contrast and color shift on liquid crystal displays at wide viewing angles.