Slow light propagation and improved performance buffering properties are obtained from photonic crystal coupled resonator optical waveguides formed by enlarged and oval rods surrounded cavities. As the radius of bulk circular rods is 0.25a (a is a lattice constant) and radius of enlarged rods is 0.35a, the group velocity of guided mode less than 2.37×10-4c (c is the light speed in the vacum) is obtained. Compared with that in homogeneous rods cavity waveguide, the maximum group velocity decreases one order magnitude. Simultaneously, buffer capacity decreases as well. Considering the buffer performances, the enlarged rods are developed into ovals to further improve the slow light properties and buffer performances. When the long axis of oval rods is 0.42a and short axis is 0.20a, the group velocity of guided mode less than 2.3053 × 10- 4c is obtained, and the buffer capacity arrives at 9.8214 bit. Q factor also reaches the maximum value 3575.1.