This paper concerns the leader-follower multiple agent formation with nonlinear and coupled individual dynamics. We address the problem of multi-agent formation control by proposing a decentralized control strategy. The agents in the formation are quad-rotors UAVs. By attributing the high-order nonlinear and unmodelled dynamics as uncertainties, we propose a switching singular system model to represent the formation of the multiple UAVs system with switching topology. For stabilizing the system with uncertainties, the decentralized controllers are designed by using Lyapunov design and redesign. The simulation results illustrate the stated problems and verify the proposed theorem.