Using iodent germplasm to improve the resource of Luda Red Bone, analyzed the Combining ability and heterosis of the main agronomic traits of five improved lines by using NC II genetic mating design。25 cross combinations were obtained by using PB-2, PB-3, PB-7, PB-8, PB-10 as female parent and Dan988, Tie0322, M54, Mo17 and Tie7922 as test varieties with strong superiority to the inbred lines. The results showed that the improved lodging line population of iodent germplasm had great utilization value. It could effectively reduce the plant height, ear height, row number of ears, increase the yield, lodging resistance, grain quality and ear length of hybrid. The parents of the improved population of Dan598 and Dan99 had high general combining ability and high yield specific combining ability, which were easy to use. Combination of high-yielding hybrid combinations has great application value in breeding.