The crosslinkable trifluoromethylated poly (aryl ethers) terminated with phenylethynyl moieties (11F-PAE-PEP)s were prepared in two step syntheses. The structure of 11F-PAE-PEP was confirmed by FTIR and H-1 NMR. The crosslinking behavior was studied by DSC. There is a remarkable increase of T-g after crosslinking of the poly(aryl ethers). The T-g values of crosslinked polymers were 437 and 446 K, respectively. The crossfinked polymers could not be soluble in common organic solvents, such as N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidinone, chloroform, and tetrahydrofuran.. The temperatures at a 5% mass loss of the crosslinked polymers in air were above 789 K. They showed a good optical property, too. This kind of polymers will be the promising materials used as the microelectronics and optical waveguide devices.