Fiber reinforced polymer composites with their outstanding performance are increasingly used in aerospace products. Currently aeronautical composites are mainly fabricated using autoclave curing technologies, but the long cure cycle, high energy consumption and large temperature gradients in composite thickness seriously restrict its further development in materials processing. As an alternative, microwave curing technology can realize a fast and energy saving curing process with less temperature gradients, and gains more and more interests in recent years. However, it was found that the microwave cured composites have very high void contents, which directly leads to huge reductions in mechanical properties. To solve this problem, a high-pressure microwave curing method was proposed in this paper. Several key technologies about the associated equipment have been introduced. Experimental results indicated that the composite voids have been significantly eliminated, and the mechanical properties of high-pressure microwave cured composites are comparable to those of autoclave cured counterparts.