The orthogonal experimental research has been carried out on the calcium ammonia catalyst for the polymerization of ethylene oxide. The influences of catalyst synthesis parameters including the m(NH3):m(Ca), m(acetonitrile):m(Ca), m(propylene oxide):m(Ca), reaction time of calcium with ammonia, reaction time of modifier on the molecular weight of polyethylene oxide and polymerization yield were investigated. From the regression analysis, it was found that acetonitrile and propylene oxide were remarkable influence factors, and the industrialized preparation conditions of catalyst were determined. The industrial tests showed good catalytic performances with high polymerization yield (> 98%) and adjustable molecular weight of polyethylene oxide from 2×105 to 8×105.