In order to precisely analyze relevant regularities and rules about how detecting probability of ballistic missile is affected by a DSP satellite under some special meteorological conditions including cloud, rain and frog, by analyzing covering range and ballistic missile detection capability of DSP satellite system, and through simulating calculations, the essay obtains with different angles of observation, how the satellite detection probability varies with strength of the precipitation, and the law of impact of the missile's flight time in active section upon DSP satellite's detection probability under the same precipitation strength, and based on the above calculations, some recommendations are given on how to make use of meteorological conditions properly so as to enhance defense penetration capability of ballistic missile in its active section.