The invention belongs to the technical field of traditional Chinese medicines and relates to Radix Astragali extract and its preparation method and preparation. The Radix Astragali extract is used for treating shortness of breath, palpitaition, collapse, spontaneous perspiration, asthenia and edema, symptoms after tumor chemoradiotherapy and operation, chronic nephrosis, chronic diarrhea, proctoptosia, uterine prolapsed, gynecological diseases, ulcer fester and nonunion wounds. The Radix Astragali extract has obviously improved content of total saponins and astragaloside. The preparation method comprises the following steps of adding water into Radix Astragali, carrying out decoction, filtering the decoction, concentrating the filtrate, adding ethanol into the concentrated filtrate, carrying out standing, collecting a supernatant, recovering the ethanol, carrying out condensation and drying, and carrying out crushing to obtain fine powder. Aiming at solving defects of the existing preparation and satisfying clinical medicine requirements, the inventor carries out detailed research. The Radix Astragali extract as an active component and appropriate medicinal auxiliary materials are processed into the preparation by the conventional processes.