This paper describes an interactive locomotion method for a biped humanoid robot. The method consists of two main parts: a pattern generator and a human-robot interface. The human robot interface is used to achieve realtime interactive locomotion. In particular, visual information and voice instructions are employed to determine locomotion parameters such as a step length, a step direction, and the number of steps. The motion of the lower-limbs is generated by the online pattern generator based on the locomotion parameters. Continuous locomotion experiments are carried out in real time using WABIAN-RV. The experimental results show the feasibility of the proposed interactive locomotion method.