Recently，the team of extreme optics, Prof. Yunquan Liu and Prof. Qihuang Gong, have study the phase structure of the tunneling wave packets from strong-field ionization of molecules and present a molecular quantum-trajectory Monte Carlo (MO-QTMC) model to describe the laser-driven dynamics of electron process in molecules. Using this model, they reproduce and explain the alignment-dependent molecular frame photoelectron spectra of strong-field tunneling ionization of N2 reported by M. Meckel et al. [Nat. Phys. 10, 594(2014)]. Besides modelling the low-energy photoelectron angular distributions quantitatively, we extract the phase structure of strong-field molecular tunneling wave packets, shedding light on its physical origin. The initial phase of the tunneling wave packets at the tunnel exit depends on both, the initial transverse momentum distribution and the molecular internuclear distance. It has been further shown that the ionizing molecular orbital has a critical effect on the initial phase of the tunneling wave packets. Since the phase structure of photoelectron wave packet is a key ingredient, this work has important implication for modelling strong-field molecular photoelectron holography, high-harmonic generation and molecular orbital imaging.