When an intense laser obliquely irradiates a solid, a pre-pulse will first ionize the solid surface, followed by the main pulse interacting with the plasma and ultimately being reflected by it. Simultaneously, certain electrons within the plasma will become trapped in the accelerating phase of the laser field, subsequently gaining effective acceleration within the field, a phenomenon known as phase-locked electron acceleration. Given the current intense lasers' electric field intensity nearing the TV/m range, electrons have the potential to acquire energy levels on the order of hundreds of GeV or even TeV if they remain in the laser field's accelerating phase for a sufficient duration. Here, we initially use PIC(Particle-in-Cell) simulations to simulate the interaction process between laser pulses and plasma, thereby obtaining the properties of phase-locked electrons. In order to reduce computational demands, we turn to use a three-dimensional (3D) test particle model to calculate the subsequent interactions of these electrons with the reflected laser field. By this model, we obtain the data of the locked-phase electrons after interacting with the reflected laser (Figure a). Furthermore, we use this model to calculate the dynamical behavior of electrons with different initial conditions (Figure b). Under the laser intensity of a ₀=350( a ₀is the normalized laser vector potential), the energy of the electrons directly accelerated by the laser was enhanced to 32 GeV. In contrast, under the same laser intensity, the energy of the electrons accelerated by ponderomotive was only 0.35 GeV. The research findings indicate that strong lasers with peak powers around 10PW can directly accelerate electrons to approximately 30 GeV. Additionally, this study outlines the optimal initial conditions for electron injection into the laser field and the final electron energy within the phase-locked acceleration mechanism, establishing a calibration relationship with the laser field intensity. Given the continual enhancement of laser intensity and the potential application of the laser phase-locked electron acceleration mechanism to positron acceleration, this research holds promise for implementation in fields such as miniaturized positron-electron colliders and high-energy gamma-ray sources.