In order to study the effects of biochar and nitrification/urease inhibitors on soil salinity and alkalinity, nitrogen availability, crop nitrogen absorption and utilization, and soil nitrogen balance in coastal saline soil, a pot experiment was carried out with barley, a typical salt tolerant crop, as the research object, a total of 9 treatments were set up in the experiment:applying no nitrogen fertilizer, conventional fertilizer, biochar + conventional fertilizer, conventional fertilizer + nitrification inhibitor DCD, conventional fertilizer + urease inhibitor NBPT, conventional fertilizer + DCD + NBPT, biochar + conventional fertilizer + DCD, biochar + conventional fertilizer + NBPT, biochar + conventional fertilizer + DCD + NBPT. The results showed that:1) All nitrogen fertilizer treatments increased salt leaching, and all biochar treatments significantly increased 10-20 cm soil EC. The soil with higher EC had lower pH, and biochar treatment slightly reduced soil pH.2) NBPT and DCD increased the grain yield of barley, and the application of biochar increased the yield of barley more but decreased the yield of straws. NBPT and DCD increased nitrogen uptake of barley plants, and NBPT increased total nitrogen contents in barley straws and grains, but decreased with biochar application, and other inhibitor treatments decreased total nitrogen contents in barley grains and straws. 3) Both DCD and NBPT improved nitrogen use efficiency, and the effects were enhanced with the application of biochar. 4) Compared with the conventional fertilizer treatment, the content of soil residual inorganic nitrogen in treatment with DCD was lower while that in treatment with NBPT was higher. DCD and NBPT added treatments reduced the apparent loss of nitrogen. Therefore, adding DCD and NBPT to urea can promote crop yield and nitrogen use efficiency in coastal saline soil, and the treatment with biochar + DCD + NBPT performs better in increasing crop yield, nitrogen efficient use and reducing nitrogen loss.