In this paper, we define a new index of dynamic manipulability for humanoid biped walking to measure dynamic flexibility of changing mechanics by using residual redundancy, when primary work is being assigned, such as face and eyes being targeted to certain object. Although some measurements have been arranged so far to evaluate statical or dynamical flexibility of hand manipulator. This paper displays a new measurement of Dynamic Reconfiguration Manipulability Shape Index (DRMSI) which is the combination of dynamic manipulability and reconfiguration manipulability, and we have applied the DRMSI into humanoid robot experiments to evaluate its dynamical reconfiguration ability during walking. According to the value of DRMSI in our experiments, we have verified our humanoid robot model is reliable and effective since the results have indicated that the kinematic and dynamic characteristics of our model are similar to human-being.