Abstract: We measure the asynchronous oscillation of an ultrasound-driven cavitation bubble by using two channels of Mie-scattering.The two scattered light intensities usually lose their synchronization.The phase-difference between intensities shows that the bubble oscillates out of step under driving of low ultrasound.As a result the large bubble does not keep its shape spherical.Fortunately,the phase-difference becomes small and to be neglectable under driving of high ultrasound.The sonoluminescing bubble oscillates exactly in step with the driving ultrasound,and there is no evidence to show its aspheric shape in our experiment.