Integrating componential factors affecting high yield with breeding practice, this article mainly probes into high yield and in breeding early and intermediate-maturing inbred line and concludes that: (1) The extension of germ plasm is the innovation basis for choosing materials for corn breeding; (2) The compactness of seed sequencing is the key to breed high combining ability inbred line maile; (3) Combining the advantages of hybrid while not restricted to it in combination, comparative observation on the yield of hybrid variety and multi-spot observation are necessary to shorten the span of breeding and to guard against “pre-upgrading”.