Abstract: The present invention relates to a new pharmaceutical composition from natural materials belonging in traditional Chinese medicine and to its preparation method. Said new pharmaceutical composition comprises Astragalus root, Pleurotus fungi, Winnged Euonymus Twig and Mulberry Leaf. At first, astragalus root, Pleurotus fungi, Winnged Euonymus Twig and Mulberry Leaf are extracted by water or alcohol to obtain extractive. The obtained extractive can be got by extracting the above four materials together, or by combining the extractive from the three materials together (stragalus root, Winnged Euonymus Twig and Mulberry Leaf) among above four materials with the extractive from Pleulotus fungi singly. Then the mixed extractive is centrifugalized and separated. If need be, the gained centrifugate can be made into oral formulations in various dose form with excipient by routine method. Said pharmaceutical composition has the effect of regulating immunity on the body.