The Sato theory of KP and KdV hierarchies is generalized to the case of matrix lax operators , leading to new hierarchies of integrable nonlinear partial differential equations, which are called extended KP and KdV hierarchies in the context. It can be seen from the construction Process, the solutions of these new hierarchies can be expressed by the so-called quasi-wrongsky determinartes, and these quasi-wrongsky determinantes are just those obtained in ou recent study of 2-extended Toda field theories.