Four copies of the sorghum sterile lines and five types of Sudan grass for parents, according to the NC Ⅱ design，were formulated to 20 hybrid combinations. Eight hybrid combinations of strong heterosis were selected with evaluation of the phenotypic value and the mid-parent advantage. heterobeltiosis Using cDNA-AFLP technology, differentially expressed genes from hybrid and parental seedling leafwere analyzed and correlated with main yield traits of hybrid performance and the heterosis. Research shows that: (1) 12 pairs of primers amplified a total of 315 TDFs, the gene expression types of sorghum-sudan grass were classified into 7 catagries: single parent expression of the same type (P1F1 type) , single parent expression with type 2 (p2f1 type), hybrid specific expression type (F1), single parent expression silence type 1(P1), a single expression silence type 2 (P2), and parents silent type (P1P2 type) and hybrid- parents joint expression type (P1F1P2 type). (2) the correlation analysis of yield components showed significant positive correlation between effective tiller number and P1F1 type, fresh weight per plant and P1P2 type; it showed significant negative correlation between leaf number and F1 type, leaf length and P2 type. the correlation analysis between mid-parent heterosis and gene types showed significant positive correlation between the spike length and the P2F1 type, fresh weight per plant with P1, P2 and P1F1P2; significant negative correlation between leaf width and P1P2. After correlation analysis with the super parent heterosis, the spike length was significantly positively correlated with P2F1, and the leaf width was significantly negatively correlated with P2F1 and P1P2. (3) differential display types of P1F1, P2F1, P1 and P2 are dominant effects, which are 91.4% of the total. Differential Display type F1 and P1P2 performance super dominance, acount for 4.8% . It indicated that the hybrid performance of each trait was mainly influenced by the (super) dominant effect. (4) 8 TDFS associated heterosis were retrieved and found homologous nucleotides with BLAST analysis, and seven homologous proteins were found important in the control of plant growth and development. (5) the nucleotide sequence was obtained by cloning and sequencing, and semi quantitative RT-PCR was used to verify the nucleotide sequence. The molecular mechanisms of heterosis were revealed, and the selecting efficiency should be improved in screening strong advantage combinationsand providing basis for the creation of germplasm resources in Sorghum-sudan grass.