Provided are an intermediate compound for preparing rosuvastatin calcium and a preparation method of the rosuvastatin calcium. The method comprises: using the foregoing intermediate compound as a raw material, and subjecting the raw material to a step of Wittig reaction, a step of protecting group removal and hydrolysis and a step of calcium salt formation, so as to obtain the rosuvastatin calcium. The product, which is prepared from the intermediate compound, can be substantially enhanced in stereoselectivity and also notably improved in purity and yield; in addition, the method for preparing rosuvastatin calcium from the intermediate compound is simple, convenient and low in cost.