Numerical methods prove useful in exploration seismology. The most commonly used numerical methods are the finite difference, finite volume, and finite element methods. These methods constitute the basis for reverse time migration and full-waveform inversion. Finite difference methods are widely used in wave field extrapolation because of their higher computation efficiency, lower memory requirements, and easier implementation. During discretization of the time and the spatial derivatives in the wave equation, grid dispersion often occurs. Grid dispersion can result in artificial waves and inaccurate wave fields. Therefore, finding suitable finite difference operator coefficients to preserve the dispersion relationship of the wave equation, thus reducing grid dispersion, is one of the most important issues when using finite difference methods. To reduce grid dispersion, the traditional method uses high-order finite difference schemes in the spatial domain. However, waves are simultaneously propagated in time and space. Therefore, some researchers propose finite difference schemes based on the time-space domain dispersion relationship. Most commonly used are the high-order Taylor expansion method and the optimized method. However, the time step is relative small even in the optimized time-space domain method. Recently, a new finite difference stencil has been proposed to increase the time step while preserving the accuracy with the least-squares method. The time-space domain dispersion relationship of this new finite difference stencil is linear. Therefore, in this paper, we propose using this improved linear method, with the new finite difference stencil, to obtain the finite difference coefficients for the acoustic wave equation. We demonstrate, by dispersion analysis and numerical simulation, that with this new FD stencil and its improved linear solution, the wave equation simulation speed can be doubled compared with the previous linear method.