【Objective】 The heterosis, general combining ability (GCA) and special combining ability (SCA) of main agronomical traits of sweet sorghum were analyzed. Meanwhile, the feasibility of heterosis prediction based on combining ability, phenotypic genetic distance (PGD) and molecular genetic distance (MGD) was estimated. The result will provide theoretical reference for germplasm improvement and hybrid breeding of sweet sorghum.【Method】 Sixty-four hybridized combinations were generated with 8 sterile lines as females and 8 restorer lines as males in accordance with a North Carolina Design II mating scheme. Twelve agronomical traits including days to flowering, growth duration, plant height, panicle length, stem diameter, tillers, panicle weight, 1000-grain weight, grain yield per plot, biomass per plant, biomass per plot and sugar content of hybrids and their parent lines were investigated in two years. The heterosis, GCA, SCA, PGD and MGD were analyzed, as well as the correlation between combining ability, genetic distance and heterosis. 【Result】 Mid-parent heterosis (MPH) of traits from high to low was: biomass per plant, grain yield per plot, panicle weight, biomass per plot, plant height, panicle length, 1000-grain weight, stem diameter, growth duration, days to flowering, tillers and sugar content. Among which, heterosis of growth duration, days to flowering, tillers and sugar content was negative. The sequence of MPH for all traits was almost the same as that of better parent heterosis (BPH). Combining ability analysis showed that the GCA of different parents varied greatly in each trait. Meanwhile, the SCA of different combinations was also significantly different. Most combinations with high SCA also showed high GCA in their parent lines. Heterosis of biomass per plant, grain yield per plot, panicle weight, biomass per plot, panicle length, 1000-grain weight, tillers and sugar content was positively and highly significantly correlated with GCA and SCA of their parent lines simultaneously. Heterosis of growth duration was positively and highly significantly correlated with SCA. Meanwhile, heterosis of days to flowering was positively and significantly correlated with SCA. The PGD of parent lines was 2.86-6.82, and MGD was 0.50-0.96. The correlation between heterosis and MGD was greater than that of PGD in biomass per plant, grain yield per plot, panicle weight, biomass per plot, plant height, panicle length, stem diameter and sugar content. Among which, heterosis of biomass per plot, biomass per plant, panicle length and stem diameter was positively and highly significantly correlated with MGD. 【Conclusion】 Heterosis of yield related traits was higher, and that of sugar content and tillers was lower among all traits. In the prediction of heterosis, combining ability was more effective than genetic distance, therefore, can be used to predict heterosis. MGD was more effective in heterosis prediction compared with PGD.