  Outflows are inevitably driven from the disk if the vertical component of the
black hole (BH) gravity cannot resist the radiation force. We derive the mass
loss rate in the outflows by solving a dynamical equation for the vertical gas
motion in the disk. The structure of a supercritical accretion disk is
calculated with the radial energy advection included. We find that most
inflowing gas is driven into outflows if the disk is accreting at a moderate
Eddington-scaled rate (up to $\sim 100$) at its outer edge, i.e., only a small
fraction of gas is accreted by the BH, which is radiating at several Eddington
luminosities, while it reaches around ten for extremely high accretion rate
cases ($\dot{m}\equiv\dot{M}/\dot{M}_{\rm Edd}\sim 1000$). Compared with a
normal slim disk, the disk luminosity is substantially suppressed due to the
mass loss in the outflows. We apply the model to the light curves of the tidal
disruption events (TDEs), and find that the disk luminosity declines very
slowly with time even if a typical accretion rate $\dot{m}\propto t^{-5/3}$ is
assumed at the outer edge of the disk, which is qualitatively consistent with
the observed light curves in some TDEs, and helps understanding the energy
deficient phenomenon observed in the TDEs. Strong outflows from supercritical
accretion disks surrounding super massive BHs may play crucial roles on their
host galaxies, which can be taken as an ingredient in the mechanical feedback
models. The implications of the results on the growth of supper-massive BHs are
also discussed.
