A simple method of vibration and stability of periodic multi-bay panels under supersonic flow has been proposed. Floquet's principle, which had been used extensively for the analysis of vibration problems of periodic structures like equally spanned beams, stiffened plates and shells has been extended in the present work to predict the vibration characteristics of multi-bay periodic panels subjected to lengthwise supersonic airflow. The solution of the differential equation of motion of panels subjected to supersonic fluid flow is substituted into the Floquet boundary conditions from which the eigenvalues involving the propagation constants are obtained. From the propagation constants the propagation bands are identified and frequency parameters for the finite panel case are obtained by a suitable discretization scheme. The simple wave approach to the solution of the problem with a comparatively small computational effort is well justified for the analysis of vibration of a large number of panels for which exact methods, finite element techniques and normal mode superposition methods involve voluminous computation. The extreme flutter limits for any number of panels are also predicted. The results obtained have been compared with existing ones and good agreement between them has been observed.