The control problem of leaderless multi-UAV formation in noisy environment is studied, and an event-triggering based strategy is adopted to reduce the number of communications and resource waste. Considering the effects of communication noise and random time delay, a Bernoulli random distribution is adopted to characterize the randomness of the occurrence of time delay. By constructing Lyapunov function and using the analysis method of linear matrix inequality, the stability conditions of multi-UAV system are given to ensure that UAVs can realize formation control under the influence of noise environment and random delay. By using the distributed control input and the neighbor information between UAVs, the system can respond and adjust quickly to form the expected formation. The algorithm is applied to the quadrotor UAV system, and the validity and correctness of the proposed algorithm are verified by theoretical analysis and simulation experiments.