The present invention relates to a process of preparing a water-soluble complex of water-insoluble or sparingly-soluble organic medicines and beta-cyclodextrin derivatives: a. dissolving successively or simultaneously the organic medicines and the beta-cyclodextrin derivatives in organic solvent(s) at certain mole ratio or mass ratio in the presence of suitable amount of water; b. removing the organic solvent from the solution of the step a to obtain aqueous solution of the organic medicine and beta-cyclodextrin derivative; and c. removing water from the aqueous solution to obtain the complex of the organic medicine and beta-cyclodextrin derivative. The invention also provides a sterile water-soluble complex of water-insoluble or sparingly-soluble organic medicines and beta-cyclodextrin derivatives. A fully-water-soluble complex can be prepared from any water-insoluble or sparingly-soluble organic medicines or other organic compounds according to the present invention. Thus, appreciably convenient means are provided for industrial uses of such organic medicine preparations and of other organic compounds.