  In this paper we give a construction of Lagrangian torus fibration for
Calabi-Yau hypersurface in toric variety via the method of gradient flow. Using
our construction of Lagrangian torus fibration, we are able to prove the
symplectic topological version of SYZ mirror conjecture for generic Calabi-Yau
hypersurface in toric variety. We will also be able to give precise formulation
of SYZ mirror conjecture in general (including singular locus and duality of
singular fibres).
