The poly(ethylene 1-octene)-g-maleic anhydride copolymers (POE-g-MAH) with high grafting degree (GD) (>9%) have previously been obtained by a solvotherrnal method in our laboratory. It is found that the low GD (less than 2.5%) did not change the bulk properties of polyolefine elastomers (POE). Thereforefore, it is worth further understanding whether a high GD POE-g-MAH copolymer differs from the pure POE in its comprehensive properties and performance. In this article, POE-g-MAH with different GDs were synthesized and characterized by thermogravimetric analyze (TGA), differential scanning calorimetry (DSC), wide angle X-ray diffraction spectroscopy (WAXD), and dynamic rheological testing. The results show that the thermal decomposition temperature, melting points, the crystallization temperatures, and the crystallinities were decreased by the increasing GD. By WAXD, three peaks respectively, attributed to the amorphous phase, the (110) and (200) interferences of the orthorhombic unit cell were detected, and they also decreased by the increasing GD. And the POE-g-MAH copolymers had higher storage modulus (G'), loss modulus (G ''), and complex viscosity (eta*) than those of pure POE. (C) 2008 Wiley Periodicals, Inc. J Appl Polym Sci 111: 1069-1075, 2009