In order to obtain high coherent narrow linewidth laser diode array (LDA) output, an effective method of in-phase mode phase-locked output is proposed by using a half period transverse offset face-to-face mutual injection Talbot cavity on LDA chip. By numerically solving the dynamic Lang-Kobayashi (L-K) rate equation of the (8+8) laser array structure, the phase-locking process of the array under different fill factors (FF) is analyzed. The results show that when the FF increases from 0.05 to 0.4, the laser units experience a process from periodic oscillation to stable phase-locking and then to chaotic state. It is determined that when the FF is between 0.08 and 0.2, the in-phase mode phase-locked can be obtained. Through the simulation of mutual injection of (8+8) laser array, it can be found that when FF=0.09-0.25, single longitudinal mode frequency locked output can be achieved, while the output spectra corresponding to other FFs are coexistence of multiple longitudinal modes. Finally, the threshold gain between different supermodels is calculated by laser intracavity transformation matrix, and the maximum threshold gain difference of the in-phase and out-of-phase modes under different FFs are determined. The results show that, for the face-to-face mutual injection phase-locked structure, when the FF is around 0.1, stable in-phase mode phase-locked can be achieved, and the threshold gain difference between in-phase and out-of-phase modes is the largest, the in-phase mode phase-locked output with the strongest robustness of the system can be obtained.Using a half period transverse offset face-to-face mutual injection Talbot cavity on LDA chip, a method of in-phase mode phase-locked output is built (Fig.1). The dynamic process of the (8+8) laser array model is calculated using the fourth-order Rung-Kutta algorithm of Matlab (Tab.1). Lumerical-Interconnect is used for laser arrays frequency locking simulation (Fig.3). Besides, the threshold gain of supermodes is calculated by laser intracavity transformation matrix under different FFs (Fig.6).Temporal evolution of wavelength and phase are studied under different FFs, the results show that as FF increased, the units experienced a process from periodic oscillation to stable phase locking, and then to chaotic state. Using the fourth-order Rung-Kutta algorithm, in-phase-mode phase-locked can be confirmed when FF between 0.08-0.2 (Fig.2). With simulation of frequency locking through mutual injection, the frequency-locked phenomenon under different FFs by output spectra can be intuitively observed (Fig.5). The results show that when the FF is between 0.09-0.25, the ideal single longitudinal mode output can be realized. After calculating the threshold gain between supermodes, the maximum threshold gain between in-phase mode and out-of-phase mode is determined (Fig.7). When FF increases from 0.02 to 0.3, the threshold gain difference between in-phase mode and out-of-phase mode rises up at the beginning and decreases in late.A face-to-face mutual injection LDA structure based on integrated Talbot cavity is proposed, and the phase-locked dynamic behavior of the structure is theoretically analyzed. By simulating units mutual injection, the output spectra under different FFs are analyzed. The results indicate that stable in-phase mode locked can be achieved when FF around 0.08-0.2. By calculating the threshold gain of supermodes under different FFs, it is found that when FF=0.1, the difference in threshold gain between in-phase mode and out-of-phase mode is the largest, indicating the FF is the optimal value for achieving single in-phase mode output. This phase-locked model and structure can be used to fabricate phase-locked laser arrays with on-chip Talbot cavity.