Abstract: Based on the stroboscopic discrete-time iterative mapped mathematic model of the current-mode buck-boost converter in period1 operation,a method is presented to determine the unstable period-1 orbit from the chaotic attractor of the current mode buck-boost switching converter.According to the theory and idea of OGY,the range of the control vector is deduced.The OGY method with the control vector selected from the range is applied and the unstable period-1 orbit embedded in the chaotic attractor of the current mode buck-boost switching converter is stabilized.