The invention discloses an astragaloside water-soluble derivative, namely astragaloside acid or medicinal salt, ester and amide of the astragaloside acid, with the structure shown in the formula 1. According to the defects that water solubility of astragaloside is poor, so that bioavailability of astragaloside is affected, and astragaloside cannot be developed into a single-component medicine, special alcoholic hydroxyl groups in astragaloside molecules are directionally oxidized into carboxyl groups ingeniously, and the astragaloside water-soluble derivative, namely astragaloside acid is prepared. A preparation method is simple in step, mild in reaction condition, small in side reaction, high in yield, easy to implement and suitable for large-scale production. The astragaloside water-soluble derivative, namely astragaloside acid or medicinal salt, ester and amide of the astragaloside acid, with the structure shown in the formula 1 has a protective function on hypoxia injuries of cardiac muscle cells cultured in vitro, and can be used for preventing and/or treating relevant cardiovascular diseases. The formula 1 is defined in the description.