Abstract: In this report, I will report our two recent work related to high Tc cuprates. In the first part, I will introduce our phenomenological theory about the quasiparticles in the pseudogap state. Two most recent angle resolved photoemission and scanning tunneling microscopy measurements on underdoped cuprates have yielded new spectroscopic information on quasiparticles in the pseudogap phase, including the particle-hole asymmetry and the possible two-gap structure. Our theory shows good agreement with these most recent experiments. Recently Li et.al., has observed the vanishing of the Josephson coupling of the CuO_2 layers in LBCO (x=1/8) happened at a temperature (54 K) well above the bulk transition temperature T_c=4K. One possible underlying mechanism is that the superconductivity on the CuO_2 planes has an array of anti-phase domain wall (πDW) with a periodicity coincidence with the stripe periodicity. In the second part of my report, I will focus on our study of the synergy among SDW, CDW and anti-phase superconductivity (APdSC) in t-J model by renormalized mean field theory, and found that under some circumstance the inhomogeneous state SDW+CDW+APdSC has the energy very close to the ground state.