Advanced wave-transparent composites are the key materials for many cutting-edge industries including aviation and aerospace, which should have outstanding heat resistance, low dielectric constant and loss as well as good mechanical properties. A novel kind of high-performance wave-transparent composites based on surface-modified aluminum phosphate AlPO(4)(KH-550) and cyanate ester (CE) was first developed. The dielectric and dynamic mechanical properties of AlPO(4)(KH-550)/CE composites were investigated intensively. Results show that AlPO(4)(KH-550)/CE composites have decreased dielectric loss and higher storage moduli than pure CE resin; in addition, the composites with suitable AlPO(4)(KH-550) concentration remain the outstanding thermal property and low dielectric constant of pure CE resin. The reasons attributing to these results are discussed from the effects of AlPO(4)(KH-550) on the key aspects such as morphology, curing mechanism, and interfacial adhesion of composites. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 123: 1576-1583,2012