Liquid phase epitaxy (LPE) of YBa2Cu3O7-x (YBCO) has been studied. The growth technique is a kind of top-seeded solution growth under a temperature gradient, which supplies the driving force for growth and achieves growth with no temperature decrease. YBCO and some other thin films can be used as seed layers, which enable us to use various kinds of materials as substrate materials. LPE grown YBCO film has higher crystalline perfection than the seed layer of YBCO. Additives to the solvent, especially BaF2, decrease the growth temperature of YBCO and decrease the reaction between substrate material and the solution.