Barrage jamming is the one of most common and serious threats for automatic dependent surveillance-broadcast (ADS-B) system. A barrage jamming suppression algorithm for ADS-B based on estimation of robust covariance matrix is proposed. Firstly, considering the pulse characteristic of ADS-B, the solution of covariance matrix is transformed into a convex optimization problem. Then, the robust covariance matrix obtained by solving the convex optimization is used to design the optimal weight vector. Finally, the barrage jamming is mitigated by spatial filtering and the performance is analyzed. Simulation results demonstrate the effectiveness of the proposed algorithm. The anti-jamming performance of this method is not limited by the prior knowledge of ADS-B direction and also effective in the case of non-Gaussian noise.