Abstract: Abstract: Biochar, which is produced by the thermochemical decomposition of organic material under a limited supply of oxygen at temperatures between 300 and 1000 ℃, has been the focus of researchers for the past several years. Each year straw of about 0.6-0.7 billion tons is produced in China, however less than half fails to reasonable use, which has resulted in a series of problems such as resource waste and environmental pollution. Converting cheap, abundant crop straw into biochar applied to soils may have significant agricultural and environmental benefits. Crop-straw biochar returned into soil not only can significantly increase carbon sequestration and reduce emission of greenhouse gases as well as protect soil quality, improve soil fertility, decrease soil bulk density and reduce the aluminum toxicity of crop in acid soil, but also provides effective way for comprehensive utilization of straw resource. In order to find out a rational solution for more and more straw in the farmland to provide scientific basis for comprehensive utilization of straw in the Huanghuai region, a field location experiment on straw biochar application was performed in the typical fluvio-aquatic soil of the Huanghuai region since 2011. Effects of continuous biochar application in 2011-2017 on growth and nitrogen absorption of winter wheat were studied. The yield components, accumulation of dry matter and nitrogen, LAI (leaf area index), chlorophyll relative content (SPAD (soil and plant analyzer development) value), and population number at the key growth stage of winter wheat, and the changes of soil organic carbon (SOC) and total nitrogen (TN) under the long-term biochar application were also observed in the test. Four treatments in the experiment were set, including BC0 (control), BC2.25 (low), BC6.75 (middle) and BC11.25 (high), which were 0, 2.25, 6.75 and 11.25 t/hm2 biochar added to the soil, respectively. The results showed that, compared with BC0, the BC2.25 increased grain yield of wheat only in 2011/2012, the BC6.75 increased grain yield in 2014/2015, 2015/2016 and 2016/2017, and the BC11.25 increased grain yield in 2014/2015 and 2015/2016. The average yield across 6 wheat seasons showed that 3 biochar application treatments markedly increased grain yield, biomass, and nitrogen partial productivity by 7.0%-8.5%, 5.2%-10.8%, and 6.8%-8.6%, respectively compared with the CK treatment, but no significant difference was found among 3 biochar treatments. In addition, biochar application treatments with middle and high addition amount also significantly increased straw yield, spike number, nitrogen accumulation of grain, straw nitrogen accumulation and plant nitrogen accumulation by 11.4%-12.6%, 10.1%-11.2%, 9.4%-11.2%, 17.4%-23.8% and 13.3%-20.9%, respectively. The roles of biochar in improving grain yield and nitrogen uptake were in accordance with response in increasing LAI and SPAD value of wheat leaves. We also found that 3 biochar application treatments increased population amount at the key growth stage of winter wheat in 2015/2016 and 2016/2017, and also increased the SPAD value and LAI at the jointing stage and heading stage in 2015/2016 and 2016/2017. Moreover, 3 biochar treatments also significantly increased SOC content in topsoil by 32.6%-215.6% in 2012-2017 and TN content by 20.0%-36.8% in 2014-2017. In conclusion, reasonable biochar application can increase grain yield and nitrogen partial productivity with promoting the growth and nitrogen absorption of winter wheat in the Huanghuai region, and also improve the soil fertility and carbon sequestration.