A total of 13 varieties and lines of maize with great diversity was used selectively as parents to make incomplete diallel crossing in accordance with the NCII method in order to make 42 combinations. Analysis of heter-osis indicated that there was higher positive heterosis than negative heterosis in these combinations. This showed that among these forty-two combinations there must be some superior combinations. A1×A18, A1×A19, A2×A3,A2×A9, A2×A18, A2×A19, A4×A9, A6×A8, A10×A19 and A14×A8 have higher heterosis. There was positive het-erobeltiosis of main agronomical characters in these combination, so value of heterobeltiosis of plot yield was bigger.