The present invention relates to a retardation film having a homeotropic alignment liquid crystal film prepared from coating a liquid crystal mixed solution containing a polymerizable reactive liquid crystal monomer on an oriented retardation film so as to improve a viewing angle characteristic of an ISP mode liquid crystal display and reduce a color shift and a method for preparing the same. There is an advantage in that since a homeotropic alignment liquid crystal film with a retardation of a thickness direction is prepared using a liquid crystal mixed solution containing a reactive liquid crystal monomer, the retardation film according to the present invention is not required for high-temperature heat treatment and cooling processes so that it can be applied to a high-speed continuous process.