Abstract: In this paper,a fusion estimation algorithm based on H-infinity theory and dynamic observer theory is proposed to estimate the center of mass sideslip angle,a key parameter in vehicle control system.The proposed dynamic observer has dynamic variables,which can improve the transient and steady-state performance of the estimation algorithm.By introducing deviation vector,constructing Lyapunov function and combining H-infinity theory,the problem of solving parameters matrix of dynamic observer is transformed into a problem of solving linear matrix inequalities(LMI).Then,a two-degree-of-freedom nonlinear dynamic model is established,which is estimated by the dynamic observer using the side-deflection angle of the centroid as the state variable.Finally,a vehicle centroid angle fusion estimation algorithm model based on H-infinity theory and dynamic observer theory is built in Simulink,and CarSim-Simulink co-simulation was carried out to verify the proposed algorithm.