Abstract: Using the two-dimensional, time-dependent quasi-electrostatic field （QEF） code, the configuration, time delay, duration and descending motion speed of quasi-static electric field caused by thunderstorm discharge was investigated, and the effects of atmospheric ionization and optical emission in mesosphere and low ionosphere caused by this QEF was also studied. Research show： the sprite halo initiates at 85 km and with a pancake-like shape, then the regions of breakdown and optical emission move downward at speed of 1.5 × 10^7m·s^-1, the regions of breakdown and optical emission gradually become an upward concave shape. Sprite halo lasts about 5.5 ms with a height range of 64-87km, and with a horizontal scale of 80 km. Moreover, simulation results indicate that appearance time of the maximum of optical emission occurs at the time of t = 2.1 ms, which is delayed to thunderstorm discharge. And the QEF does not monotonously decrease with the altitude increasing, it has complicated structure at symmetrical axes. In addition to, the QEF cause atmosphere breakdown ionization and lead to electron density increases （ionization coefficient 〉 attachment coefficeint） or decreases （attachment coefficient 〉 ionization coefficient）. At altitude of 70 km, the increased electron density of Ne = 2.178 × l0^8 m^-3 is much bigger than the fair weather electron density of Ne = 6.329 × 10^5 m^-3.