Aiming at the problems of cross-influence between the two output branches va and vb of the single-inductor dual-output Buck-Boost converter and poor transient performance， an active disturbance rejection control （ADRC） strategy based on cascaded extended state observer （CESO） is proposed. First， according to the ADRC theory， the main road and the branch roads are fitted as independent systems to reduce the cross-influence between the branches. Secondly， CESO is designed to estimate the total disturbance of the system to eliminate the observation residual error caused by the incomplete estimation of the traditional extended state observer， CESO is also used to suppress the high-frequency noise of the circuit sensor to further improve the estimation accuracy of the observed value， and then the observed value acts on the state error feedback control rate of ADRC to improve the transient performance of the system. Finally， the closed-loop stability of the control system is proved by the Lyapunov theory. The simulation results show that the control strategy proposed in this paper effectively reduces the cross-influence between the two output branches va and vb， and improves the transient performance of the system at the same time.