This study investigated tar content of 205 flue-cured tobacco germplasm accessions which were collected from Shandong province and Sichuan province, China. Seventeen low-tar flue-cured tobacco germplasms such as Wolihuang 0782, P3, Qiannan No.7, 82-3041 and Jiyan No.10 were identified by deployment of multiyear and multiple location experiments. Furthermore, the agronomic traits including plant height, leaf number and stem diameter were scored, and six conventional chemical components in the cured tobacco leaves were examined. The correlation between agronomic traits, chemical composition and tar release was investigated by using simple correlation analysis, path analysis and regression analysis. An extremely significant positive correlation was revealed between tar release and any of nicotine, total sugar and reducing sugar. An extremely significant negative correlation was detected between potassium and tar release, while Chlorine was significantly and negatively correlated with tar release. No significant correlation was observed between other factors and tar release. The tar release were contributed by potassium, followed by total sugar, nicotine, middle leaf length, chlorophyll, stem diameter as well as plant height. Potassium and total sugar mainly affect tar content through direct action. The direct and indirect effects of nicotine to tar release are similar. Agronomic traits including waist length, chlorophyll and stem diameter can indirectly affect tar release, and other factors showed no obvious effect on tar content. Finally, a regression model between agronomic traits, chemical composition and tar release was proposed, which is of importance for the screening and utilization of low-tar flue-cured tobacco germplasm.