To enhance the accuracy of seismic wave numerical simulation and elastic reverse time migration (ERTM), this paper constructs a staggered-grid compact finite difference (CFD) scheme for solving the first-order stress-velocity elastic wave equations in two-dimensional isotropic media. Through theoretical derivation, the difference coefficients, dispersion characteristics, and stability conditions of this scheme are determined, and a comparative analysis is conducted with conventional finite difference (FD) schemes of the same order. The study demonstrates that within the high-wavenumber range, the CFD scheme exhibits significantly higher accuracy than same-order FD schemes, effectively suppressing numerical dispersion. Remarkably, even low-order CFD schemes can surpass the accuracy of high-order FD schemes. Although the stability condition for same-order CFD schemes is more stringent (permitting a slightly smaller maximum time step), their suppression effect on numerical dispersion is particularly prominent in marine seismic models containing low-velocity seawater layers, substantially improving the simulation accuracy of key wavefield information such as reflected waves. The effectiveness of the CFD scheme is verified by forward modeling and ERTM experiments using the Marmousi model: seismic records simulated with this scheme exhibit markedly reduced dispersion effects, and the imaging results align more closely with the reference standard. This proves the scheme"s applicability for high-precision seismic wave numerical simulation and ERTM, providing an effective solution for high-accuracy seismic data processing in complex marine scenarios.