Now available research on the resilience in Command Information System is in ignorance of the impact of demand changes on its resilience process, and is unable to reflect the relationship between the resilience ability of the system after being attacked and task requirements. Three variables of normal performance, lowest performance and expected performance are introduced, and three resilience models of significantly increased demand, basically flat demand and significantly decreased demand are proposed. In view of the two stages of functional level decline and adaptive recovery in the process of resilience, a strategy of resistance enhancement and redundancy enhancement strategies is proposed, the measure effect function is defined, a resilience optimization model is established, and the approximate dynamic programming algorithm of the group knapsack problem is used to solve the problem. Taking a certain of Regional Joint Air Defense Command Information System as an example, a simulation experiment is conducted, and the impact of demand changes on the resilience optimization of the Command Information System is verified. The results show that in order to adapt to the operational requirements of different scenarios in complex and harsh battlefield environment, the Command Information System should select a reasonable resilience mode, and the comprehensive relevant factors, such as enemy's attack intensity, funding budget, coping strategies, and so on, should be taken into account.