  I present a microscopic theory I proposed recently to describe high-T_c
superconductivity in cuprates. I show that coherent pairing states consisting
of extended singlet Cooper pairs and triplet $\pi$ pairs can manifest both the
Mott insulating antiferromagnetic order and the d-wave superconducting order.
  From this configuration of coherent pairing states, I can describe both the
single electron properties and the low energy collective excitations in high
T_c superconductivity in the same framework. The quasiparticle can be derived
directly with respect to the coherent pairing states. While, the low-lying
quantum fluctuations associated with spin-wave and charge excitation can be
investigated from the path integral of the coherent pairing states.
