Catalysts can enhance the reaction rate and make efforts in a certain direction into biodiesel synthesis. Solid catalysts have advantages compared with liquid catalysts, one of those can be regenerated. Catalyst regeneration can be carried out using desorption and calcination. The purpose of this study was to observe the effect of various solvents in desorption and temperature on calcination in regenerating the CaO/K2O-TiO2/H composite catalyst after it used for biodiesel synthesis from used cooking oil (UCO) in a one-step esterification and trans-esterification process. The catalyst was prepared by CaO prepared from eggshell which is impregnated by KOH and loading TiO2/H to form a CaO/K2O-TiO2/H composite. The composite is used as a catalyst for converting UCO into biodiesel in a one-step process. Furthermore, the catalyst of the process was regenerated with ethanol and acetone desorbed and calcined at 400, 500, 600 and 700oC. The results showed that the acetone desorbed after using catalyst in cycle-3 was higher biodiesel yield of 65.32% than ethanol (60.47%). The calcination temperature also has an effect in increasing the conversion ability into biodiesel, the highest at 600oC of 84.86% biodiesel yield. The performance of catalyst for synthesizing biodiesel can be increased by solvent desorbed and calcination methods, so that it is important considered.