Abstract: The hydrogenation of diene compound and carbonyl group with yeasts was studied. The partly hydrogenation of geraniol to citronellol and the reduction of benzaldehyde to benzyl alcohol were chosen as model reactions. It shows that Bakers yeasts, XST-KO yeasts and candida2# can catalyze the partly hydrogenation of geraniol to produce citronellol, and candida1#, candida2#, Hansenula anomala, XST-KO yeasts, distillery yeast and bakers yeasts can catalyze the hydrogenation of benzaldehyde to yield benzyl alcohol.These resuluts are important to catalysis with microbial cells in organic solvents.