Entangled optical field generated by a non-degenerate optical parametric amplifier (NOPA), has been considered as an important resource of continuous variable quantum information research. With the development of quantum networks and quantum computation, multi-partite entangled states with more sub-modes are required to complete more complex research of quantum information. Generally, Multi-partite entangled states can be obtained by means of coupling several Enstein-Podolsky-Rosen (EPR) entangled states or squeezed states with classical coherence through different beam splitters. The threshold of the NOPA is reduced from 250 mW to 45 mW by using a wedged nonlinear crystal. When pumping power is 23 mW, the correlation noises of quadrature amplitude and quadrature phase of the EPR entangled optical fields are 5.5 dB below the corresponding quantum noise limits. Thus we can pump much more NOPAs with only one laser source and obtain the multi-partite entangled states as needed.