Abstract: A dynamic analysis monitoring technique is presented for autoclave cure process of composites constructed of T300/8DTT carbon-fiber epoxy resin pre-preg.On the basis of the monitoring technique and with a domestic monitor model JK2107,the appropriate time of pressure application can be chosen and then the "optimum band of pressure application" can be determined successfully by a small number of experiments.During cure process of thermosetting resin system,a dielectric loss tan- gent vs time curve can be obtained with the monitor and the "optimum band of pressure application" can be found from the curve.Thus it is po-ssible to choose the proper time of pressure application by the loss tangent,and composite plates with a low void content are made by monitoring the time chosen.This paper proposes a new way to move the optimum band of pressure application" to the peak of loss tangent curve or behind it by increasing frequency given by monitor JK2107 and to use the peak of the curve as a reference signal.Therfore,the time of pressure application can be controlled exactly and the quality of composite plates is guaranteed steadily in this way.