The fire distribution is divided into weapon allocation and iirmg time scheduling. The prin?ciple of weapon allocation is that a target with greater threat value has higher priority. And the princi?ple of firing time scheduling is a target can be damaged at the expected probability before a specific time. A fire distribution scheme and a computing program for the missile-gun system under the princi?ple of earlier damage were presented for the first time. An example was taken to illustrate the effec?tiveness of the model.