A new experiment has been designed on the basis of the polarization in an ion-blocking electrode condition, which allows one to simultaneously determine the ionic charge-of-transport (alpha(1)*) and chemical diffusivity ((D) over tilde) of a mixed conductor compound, A(1-delta)O, tested for the first time on the system of Co1-deltaO. The workability and promise is verified by the preliminary results, alpha(1)*=0.357 and (D) over tilde=1.98x10(-6) cm(2)/s at 1200 degrees C and P-o2=10(-3.63) atm, which generally agree with reported values.