  We calculate the lifetime of both the o-Ps and the p-Ps positronium
annihilation decay $ Ps\to\gamma\gamma$ in the strong circular polarized laser
field. We take a strategy of the factorization to separate the effects caused
by the Coulomb interaction and the strong laser field interaction. It is
factorized in the time direction but not in the space direction. Our results
show that in the laser with long wavelength and high intensity, the lifetimes
of those Ps states are dramatically increased. For $\rm CO_2$ laser with $10\,
\mu m$ wavelength and $10^{13} W/cm^2$ intensity, lifetime of the spin-single
positronium is increased by $10^8$ times. Our result is consistent with those
obtained by solving the Sch{\"{o}}dinger equation. This effect may be useful
for the high harmonic generation(HHG) effects provided with the
Ps\cite{keitel2004}.
