The invention discloses a preparing method for a high-emissivity ceramic coating on the surface of a titanium alloy matrix. The method includes the steps that pre-grinding, acid pickling and flushingare sequentially conducted on the surface of a titanium alloy; secondly, water is added into sodium hexametaphosphate, sodium silicate and potassium fluozirconate to prepare an electrolyte; and thirdly, the titanium alloy is put into a stainless steel electrolytic cell, then the electrolyte is added, the titanium alloy serves as an anode, the stainless steel electrolytic cell serves as a cathode,a pulse micro-arc oxidation power device is used for conducting micro-arc oxidization on the surface of the titanium alloy to prepare the high-emissivity ceramic coating. By means of the preparing method, the micro-arc oxidization technology is adopted for introducing components in an electrolyte solution in the coating on the surface of the titanium alloy, in addition, the uniformity and compactness of the ceramic coating on the surface of the titanium alloy matrix are successfully achieved through step-by-step constant-pressure control and adjustment of the proportion of all components in the electrolyte solution, and the titanium alloy surface ceramic coating with high emissivity and good combination force is prepared.