We directly develop the wave function of EPR (Einstein et al., Phys. Rev. 47, 777 1935) into a state vector with the use of the method of integration within ordered product (IWOP) of operators. We find that this kind of states is normalized as an orthogonal complete set which is capable of constituting an entangled state representation; its Schmidt decomposition is derived, and its application for explaining two-mode squeezing is presented. Furthermore, with the aid of the bosonic mode conversions in two different coordinate frames, we show that the 2d coordinate or momentum eigenstate can appear as the form of the entangled state.
