  We report the quantum transport properties of the $\alpha$-Sn films grown on
CdTe (001) substrates by molecular beam epitaxy. The $\alpha$-Sn films are
doped with phosphorus to tune the Fermi level and access the bulk state. Clear
Shubnikov-de Haas oscillations can be observed below 30 K and a nontrivial
Berry phase has been confirmed. A nearly spherical Fermi surface has been
demonstrated by angle-dependent oscillation frequencies. In addition, the sign
of negative magnetoresistance which is attributed to the chiral anomaly has
also been observed. These results provide strong evidence of the
three-dimensional Dirac semimetal phase in $\alpha$-Sn.
