Identification of salt-tolerant germplasm resources was the major consideration for salt-tolerant breeding, and was also the prerequisite and basis for the research on salt-tolerant mechanism and genetics in foxtail millet. In this study, 10 germplasms were treated with NaCl solution of different concentrations, and 4 indicators, including the relative germination potential, relative germination rate, relative shoot length and relative root length, were analyzed, and the results showed that the suitable NaCl concentration for the identification of salt tolerance at germination stage in foxtail millet was 180 mmol/L. In order to evaluate salt-tolerance of 180 core germplasms at germination stage, correlation analysis and principal component analysis were used for calculating the four indicators above under the treatment of 180 mmol/L NaCl. The comprehensive evaluation and salt-tolerant grade of 180 germplasms were identified by membership function analysis and cluster analysis, and the results showed that extremely significant positive correlation was observed among the relative germination potential, relative germination rate, relative shoot length and relative root length under stress of 180 mmol/L NaCl, and furthermore, principal component analysis indicated that the four indicators above could be thought as important indexes for evaluation of salt tolerance. And then cluster analysis revealed that 180 germplasms were divided into four groups: highly salt tolerant, salt tolerant, salt sensitive and extremely salt sensitive. Five of which, Jiangu, Hengu 12, Qitoubai, K-3606 and Jingu 20, were selected as extremely salt tolerant accessions by comprehensive evaluation through membership function. In addition, under 180 mmol/L NaCl stress, fourty lines from the F7
generation recombinant inbred line (RIL) of "Heizhigu (extremely salt-sensitive) × Changnong 35 (salt-tolerant)", were analyzed and it was found that there was significant variation among 40 lines and their frequency distribution of salt tolerance grades was approximately normal, indicating that this population was suitable for salt-tolerant QTL mining. Those findings show that 180 mmol/L NaCl can be used for the identification of salt tolerance of germplasm at germination stage in foxtail millet and under this concentration, the differences in salt tolerance of different germplasms can be better distinguished by four indicators: relative germination potential, relative germination rate, relative shoot length and relative root length, which lay an important foundation for the screening of salt-tolerant germplasms and the analysis of salt-tolerance mechanism at germination stage in foxtail millet.