Three types of maize grains from high yield maize (HYM), high protein maize (HPM) and high oil maize (HOM) were used in the present study to compare their chemical compositions, starch gelatinization and in vitro ruminal fermentation characteristics based on chemical analysis and the in vitro gas production method. The results showed that the type of maize had signifi cant effect (P<0.05) on the contents of CP, ether extract and starch, starch gelatinization, 48-h gas production, rumen fermentation rate, potential gas production, 12-h and 24-h in vitro ruminal digestibilities of dry matter and starch. Of three types of maize grains, HYM had better merits than HOM and HPM in most energy traits, though almost all in vitro ruminal fermentation parameters including pH, NH₃-N, VFA concentration and molar percentages of individual VFA were not significantly different (P>0.05) among maize types. It was concluded that compared with other two types of maize grains, high yield maize hybrid showed a great potential to be used as energy feed source of ruminant animals.