This paper deals with the walking control of biped robots inspired by biological concept of central pattern generator (CPG). A control architecture is proposed with a trajectory generator and a motion engine. The trajectory generator consists of a CoG (center of gravity) trajectory generator and a foot trajectory modulator. The CoG generator generates adaptive CoG trajectories online and the foot trajectories can be modulated based on the generated CoG trajectories. A biped platform NAO is used to validate the proposed locomotion control system. The experimental results confirm the effectiveness of the proposed control architecture.