The present invention provides a preparation method for PCV2 capsid protein and a pharmaceutical composition containing said capsid protein. The method of the present invention uses a novel arabinose-induced expression vector and thereby improves the syethsis efficiency of said PCV2 capsid protein. On the other hand, the present pharmaceutical composition combines said capsid protein and other favorable components at a proper ratio so that achieves excellent immune-inducing effects.本發明提供一種豬第二型環狀病毒之外鞘蛋白質的製備方法及含該外鞘蛋白質的醫藥組合物。本發明方法係透過使用一新穎之阿拉伯糖誘導表現載體,從而提高豬第二型環狀病毒之外鞘蛋白質的合成效率。另一方面,本發明醫藥組合物以合適比例組合前述外鞘蛋白質及其他有利成分而取得優異的免疫誘發效果。