Eight Dutch surface soils were used in this study to analyse different N fractions in 0.01 mo1L^-1 CaCl₂ extracts and percolates at different temperatures.The results obtained showed that:(1)The temperature of 0.01 mo1L^-1 CaCl₂ extracting and percolating solution had no influence on amount of NO₃^--N,the extractability of other N fractions (NH₄^2-,total soluble N and reduced N),however was evidently affected by the temperature in 0.01 mo1L^-1 CaCl₂ solution.The hydrolysis of organic N was the predominant reason for this influence.(2) The release of organic soluble N obeyed the first order kinetics.A nonlinear least square method could bestfit the experimental data into the model N_t=N₀(1-e^-kt) with Rsquared being than 0.99.(3) The kinetic values No were highly consistent with the soluble reduced N in extraction exeperiment.The 0.01 mo1L^-1 CaCl₂ sollution exetracted and released the labile organic N fraction.The determinations of soluble orgaraic N in 0.01 mo1L^-1 CaCl₂ solution looked promising as a property for prediction of N mineralization,N fertilization and N pollution.