In this study, eight agronomic characters (including plant height, leaf number, panicle length, panicle diameter, panicle weight, grain weight per panicle, branch number per panicle and grain number per branch) of 160 foxtail millet germplasm resources were investigated at three environmental conditions (Ledong, Hainan province; Luoyang, Henan province; Gongzhuling, Jilin Province) from 2015 to 2016. Their broad-sense heritability were estimated by simultaneously considering the years, latitude environments and genotypic variations, and the genetic relationship among these traits was analyzed. The average heritability at each of eight traits using single-factor analysis method was over 0.9 at years and latitude environments. While no variation on individual heritability at eight traits was detected at Ledong (low latitude environment), for the traits panicle length, grain number per branch and panicle weight, grain weight per panicle as well as branch number per panicle this factor the significant variation on individual heritability was detected at Luoyang and Gongzhuling. Several traits such as plant height, leaf number, panicle length, panicle diameter, and branch number per panicle showed higher heritability, whereas the traits including panicle weight, grain weight per panicle, and grain number per branch were detected with moderate heritability. Under three-factor combined conditions, the average heritability decreased from 0.9 to 0.7266-0.8483, and the individual heritability decreased from 0.5209-0.9931 to 0.2292-0.4263. The characters including plant height, leaf number and panicle diameter were qualified as indexes in ecological adaptability breeding in foxtail millet. The plant height, leaf number and panicle diameter positively correlated with either of panicle weight and grain weight per panicle (P < 0.001). Thus, selection for plant height, leaf number, panicle diameter and heading date might achieve the selection of panicle weight and grain weight per panicle in breeding for ecological adaptability, stable yield or high yield cultivars in foxtail millet.