Outgoing surface long-wave radiation (Rlu) is an import component of surface radiation budget,unfortunately,a good many observation sites lacking this meteorological data.Therefore,a simple and accurate model for calculating Rlu is essential and significative.Based on two-year observation of outgoing grass land surface long-wave radiation and screen-level air temperature (ta) at SKYNET Hefei site,the empirical relations between Rlu and ta have been statistically analyzed.Results indicated that there being excellent linear correlation between Rlu and ta,and the liner correlation coefficients R between daily mean Rlu and ta are higher than 0.98 for each season,the standard deviation of regression lines less than 5.0W·m-2.A parameterization for calculating Rlu based on ta has been proposed and it′s feasibility has been demonstrated using observed data during the period of September 2004 to August 2005.The results indicated that the root mean square errors and mean percent errors of calculated Rlu less than 5.5W·m-2 and 1.3% for each season with the degree of agreement for observed and calculated value higher than 0.954.The scheme is proved to be valid and feasible and it has significant reference value for regions and/or period of time in defect of Rlu observation data.