We propose a coherent resonant tunneling model in double-barrier nanos
tructutes in which besides an interference effect originated from cohe
rent tunneling of single electron through two barriers, the effects of
one-electron charging, discrete energy spectrum and electron interact
ions between barriers are also important. The interference effect, lik
e that for light in Fabry-Perot cavity, will occur no matter whether a
magnetic field exists or not, and is shown to have significant effect
on the systems' tunneling current. Our model agrees surprisingly well
with all the main experimental features of the phenomenon discovered
by Scott Thomas et al.