On the problem of mission control of the multi-UAV system in a dynamic environment, the method of Dynamic Task Allocation and Coordination (DTAC), based on the combination of market mechanism and alliance recruitment, is proposed. On the basis of the DTAC model of multi-UAV system, constructed with the application of market negotiation, the physical object of the market negotiation mechanism is substituted by that of alliance recruitment. Furthermore, the recruiter is empowered to coordinate within the alliance, which reduces the auction times and increases the efficiency of DTAC. The result of simulation shows that the method can effectively solve the problem of dynamic mission control of the Multi-UAV system.