Abstract: In this article,clutch size,nesting success and breeding success rate of Emberiza jankowskii living in grassland habitats in Baicheng Region of Jilin Province were studied from May to July in 1999. The results showed average clutch size was 5.09?0.58 eggs per nest. There was negative correlation between clutch size and initial laying date,brood quantity and initial laying date,clutch size and fresh egg weight. There was exceedingly negative correlation between initial laying date and incubated rate. There was exceedingly positive correlation between nest size and clutch size. There was positive correlation between other attributes of nest and clutch size. Average incubation period was 12?094 days, incubated rate was 36.3%,and breeding success rate was 11.11%. The population size of brood size above seven days was 2.56?1.53. Nestling survival rate was 27.69%.