With the combination of optimal control theory and multi\|configuration time-dependent Hartree（MCTDH） method, the vibrational quantum model for describing the multidimensional planar structural PTCDA molecule is constructed. Within the frame of MCTDH, the dynamics of PTCDA ground state via pump-dump process under an excitation of femtosecond laser pulse is considered. The relation of reduced control yield of target state to the shape of excitation pulses, the propagation time and the effective energy of optimal field are analyzed theoretically. The wavepacket distributions in the involved vibrational coordinates are compared with the vibrational parameters. It is found that with longer propagation time, higher control yield of target state at lower strength of optimal pulse is realized, which provides an effective method to realize the control with low energy laser pulses in experiment.