The primary parametric resonance of the timedelayed velocity feedback control on piezoelectric beams under axial excitation is studied. Based on Hamilton principle, the parameter vibration equations of the controlled piezoelectric beam are obtained. The multiscale method of the nonlinear vibration is used to study the subharmonic primary parameter resonance on the piezoelectric beam, and its stability regions are examined. The numerical example is given to investigate the effects of time delays, control gain and axial force on the stability region and obtain the time history curves of the primary parametric resonance on piezoelectric beams. The results show that the increase of time delay leads to the reduction of the axial force of the system, while the control gain exhibits opposite effect. Moreover, with the increase of the axial force, the active damping increases in a certain range, and the timedelayed feedback can effectively reduce the response amplitude.