In China, there are increasing needs for greater genetic diversity of maize (Zea mays L.) germplasm and for hybrids appropriate for machine harvesting. to test and distinguish American maize inbred lines with exceptional combining ability, Four Chinese maize inbred lines (Chang7-2, Zheng 58,four-144 and four-287) were used to judge combining ability and heterosis of 16 U.S.A inbred lines by a NCII genetic mating method. The result showed: Among the American inbred lines, 6M502A,LH208,NL001,LH212Ht,PHW51,FBLA and LH181 showed excellent GCA for yield characteristics; while RS710,PHP76,FBLA,and PHJ89 showed excellent GCA for machine harvesting characteristics. In hybrid combinations, NL001×Chang7-2,LH212Ht×Chang7-2,FBLA×four-144,LH181×four-287,PHK93×four-287 had better SCA for yield characteristics; while NL001×Chang 7-2,6M502A×Chang7-2,LH212Ht×Chang7-2,LH181×four-287,PHW51×Chang7-2 were better than the check for machine harvesting characteristics. NL001×Chang7-2, 6M502A×Chang7-2,LH212Ht×Chang7-2,LH181×four-287,PHW51×Chang7-2 showed excellent total combined advantages compared to the check and potential for future utilization in Inner Mongolia corn production.