Novel cyclic olefin copolymer (COC) with high glass transition temperature, good mechanical performance, high transparency, and excellent film forming ability has been achieved in this work by effective copolymerization of ethylene and exo-1,4,4a,9,9a,10-hexahydro-9,10(1',2')-benzeno-1,4-methanoanthracene (HBMN). This bulky cyclic olefin comonomer can be simply prepared in good yield via Diels-Alder reaction. By utilizing constrained geometry catalyst (CGC) activated with Al(Bu-i)(3)/[Ph3C][B(C6F5)(4)], ethylene/HBMN copolymer can be obtained with excellent production, high molecular weight, and a wide range of HBMN incorporation. C-13 NMR (DEPT) spectra reveal alternating ethylene-HBMN sequence can be detected at high HBMN incorporation. The glass transition temperature (T-g) of resulted copolymer enhances with increasing HBMN incorporation. A high T-g up to 207.0 degrees C is attainable at low comonomer incorporation of 30.4 mol %, which is 61 degrees C higher than that of commercial norbornene (NB)-derived COC (54 mol %). The tensile test indicates that the ethylene/HBMN copolymer has good mechanical performance which is more flexible than ethylene/NB copolymer and the previously reported COC even at a higher T-g level.