Abstract: Recently, kilometer-scale Martian ionospheric irregularities have been measured by the Mars Atmosphere and Volatile EvolutioN (MAVEN) mission (Fowler et al., 2020). In this study, we carried out a simulation of these irregularities, assuming a uniform Martian zonal neutral wind and a cosinusoidal perturbation of the plasma density as the seeding source. Results show that a vertical electric field shear could be induced by such a plasma density perturbation. We find that the vertical electric field shear causes a velocity shear of the plasma between the topside and bottomside ionosphere, which in turn is able to produce kilometer-scale ionospheric irregularities — irregularities of a smaller scale than were seen in previous simulations (Jiang CH et al., 2021). These kilometer-scale variations with altitude, in plasma density and magnetic field profiles, are comparable to the MAVEN observations.