Primary Korean pine (Pinus koraiensis) forest is climax community of Xiaoxing'an Mountains, in northeast of China. It has significant influence on regional ecology and hydrological environment. In order to investigate the canopy interception and allocation and evaluate forest hydrological function and benefit of virgin Korean pine forest quantitatively, positioning experiments were implemented during two rainy seasons of from 2010 to 2011 in Liangshui national nature reserve. Throughfall, stemflow and precipitation were measured and interception loss was subsequently calculated. On the basis of the observations of 21 rainfall events which collected from local weather station and forest stand respectively, we stimulated canopy interception process of virgin Korean pine forest in the Xiaoxing'an Mountains using the modified Gash model. The mesured values of total preciptation, througfall, stemflow, and canopy interception loss in virgin Korean pine forest of Xiaoxing'an Mountains were 514.1 mm, 373.19 mm, 8.02 mm, and 132.43 mm, respectively, during the study period. Throughfall and stemflow were all significantly positively correlated with precipitation (P<0.01). The simulated values of throughfall, stemflow, and interception loss by modified Gash model were 370.91 mm, 16.14 mm, and 130.07 mm respectively. Simulation value of throughfall was 2.28 mm lower than the actual value, with a relative error of 1.75%, while simulation value of stemflow was 8.12 mm higher than the measured value, with a relative error of 50.3%. The simulated value of canopy interception loss was 2.35 mm lower than the actual value, with a relative error of 1.81%. The stimulated values of throughfall and canopy interception corresponded well with measured values, while for stemflow, the simulated value was of great difference from measured value. Our findings reveal the Gash analytic model can be well applied to estimation of canopy interception loss of virgin Korean pine forest during rainy seasons in the Xiaoxing'an Mountains.