As there are strong crustal magnetic fields in some Martian concentrated regions. it has long been a goal of Martian science to understand how crustal magnetic field affects surrounding space environment. In the paper, using the data measured by MAVEN, the ratio of electron/CO₂ density ( N_e/N_CO2) in region with different levels of Martian ionospheric magnetic fields are studied. It seems that ratio of dayside N_e/N_CO2 in region with stronger ionospheric magnetic field is larger while the altitude is more than 260 km. On the other hand, the effect of crustal magnetic field intensity on the nightside ratio of N_e/N_CO2 is weak. Since the topological structure of magnetic field is very vulnerable to the solar wind, the correlation between N_e/N_CO2 and solar wind parameters are analyzed. We find that there is obvious negative correlation between dayside ratio of N_e/N_CO2 and solar wind dynamic pressure in the region with strong ionospheric magnetic field, which may imply that the ionospheric plasmas are significantly escaped in response to enhanced solar wind dynamic pressure pulses in the dayside region. However, the effect of solar wind on nightside ratio of N_e/N_CO2 is very little. These results can be useful for understanding the dynamic process in the Martian ionosphere.