We studied the breeding ecology and offspring sex ratio of Jankowski′s Bunting (Emberiza jankowskii) at Jarud Banner in Inner Mongolia during the breeding season of 2012 and 2013. Sex ratios of 12 nests with 59 offspring were identified by sequences amplified from CHD gene using the primer pair of sex1’ and sex mix. Additionally, we used one-sample Kolmogorov-Smirnov test to judge if the sex ratios in 2012 and 2013 were normally distributed, and one-sample T test to calculate the average clutch size and female sex ratio. All of these were done via SPSS 21.0. In our study area, the earliest first-egg date varied from 13th May to 12th June; the average clutch size was 5.1 ± 0.6 (4﹣6, n = 51). The average hatching period was 11.5 ± 0.7 d (10﹣12 d, n = 19), 13 (43.3%) and 15 (50%) nests fledged successfully in 2012 and 2013, respectively. Natural predators, abandon nests were the two main factors for nesting failures of Jankowski′s Bunting. The sequence length of Jankowski′s Bunting′s CHD gene was next to 170 bp, with part of the results showed in Fig. 1. According to the breeding sex ratio analyses from five nests in 2012 and seven nests in 2013, the breeding sex ratio was 1.20 ± 1.08 (1.50﹣4.00, n = 5) in 2012 and 0.86 ± 0.65 (0.25﹣2.00, n = 7) in 2013, the overall breeding sex ratio was 1.38 ± 1.03 (0.25﹣4.00, n = 12). In the one-sample Kolmogorov-Smirnov test, all the three ratios mentioned were normally distributed (P values were 0.62, 0.44 and 0.72). Based on the K-S test′s result, the sex ratio were not differed significantly in one sample T test, with P values 0.14, 0.13 and 0.24 respectively. So, we suggest that the sex ratio of Jankowski′s Bunting offspring tends to be stable to 1︰1. Besides, we provided conservation suggestions on enhancing the breeding success of Jankowski′s Bunting.