Aiming at the influence factors of the ejecting velocity of submarine-launched missile, the accurate ejecting velocity model of submarine-launched missile is established. Using simple correlation analysis and partial correlation analysis, according to the actual measured data, factors including the depth of launch, convective navigational speed of submarine, ocean current velocity over the ground, ocean current direction, sea condition (valid wave height) were made correlation analysis and the notable relevant factors of ejecting velocity were found out. This research result played instructional role on reliable ejection of submarine-launched missile.