There has been much interest in the Si-based strained materials lately, which was widely adopted in the high-speed and high-performance devices and circuits. Based on the valence band E（k）-k relation of strained Si/（001）Si1-xGex, the hole effective mass along arbitrarily k wavevector direction were obtained. It was found that in comparison with relaxed Si, the obvious change occurs in the hole effective mass of first and second valence band in strained Si/（001）Si1-xGex along specific k wavevector directions. The hole effective mass plays a significant role in the hole mobility enhancement. The results can supply valuable references to the investigation on the Si-based strained PMOS device performance and the conduction channel design related to stress and orientation.