Based on the introduction of the characteristics of Fengyun-3 E star (FY3E) day/night orbit meteorological satellite and low-light imager and according to FY3E orbit parameters, the Satellite Tool Kit (STK) simulation technology is used to simulate and analyze the external stray light, which comes from the sun and the moon and enters into the remote sensor (low-light imager) loaded in FY3E. The method of light shield is proposed to suppress the stray light. The results indicate that the stray light has the greatest impact on the remote sensor on 2016-12-18 when the angle between the sun vector and the normal vector of remote sensor bottom window is minimal. The effect of stray light caused by the moon on remote sensor is further analyzed, and it can be avoided when the sun shade condition is satisfied. Therefore, when we design the shade, the angle between the sun vector and the normal vector of remote sensor bottom window is only needed to consider. At present, the field-of-view of the remote sensor is 55°, and the efficiency of shading stray light is low. To improve the shading efficiency of stray light and not affact application, the field-of-view of the remote sensor should be reduced to 50° and the size of the light shield should be decreased.