<p>This paper addresses the distributed security cooperative formation control for quadrotor unmanned aerial vehicles (UAVs) in a complex environment. A distributed model predictive formation control method with an event-triggered mechanism is proposed to reduce the number of times to solve the optimization problem. It is realized by incorporating the pre-set formation equation into a cost function that considers the change of control quantity. Considering the collision and obstacle avoidance problem during the operation of formation, a method is constructed through adding soft and hard constraints to the cost function according to the prediction results and the on-demand, so as to reduce the operation time of quadratic programming solution. At the same time, the feasibility analysis and stability proof of distributed model predictive formation control with event-triggered mechanism are carried out from the optimal theory and Lyapunov stability method. Finally, simulation results on formation with a group of quadrotor UAVs are given to verify the effectiveness of the theoretical results.</p>