Based on 3-year continuous observations

the runoff characteristics of Pinus armandii man made plant community are researched

and the results are listed as follows: The season distribution of precipitation in the area is uneven

the rainfall of wet season (from Jun. to Oct.) accounts for 80% of yearly gross

the precipitation is mainly brought by rainfall with more than 10mm

and most of the rainfall intensities are less than 5.0mm/h. Monthly change tendency of runoff is similar to precipitation

and the relativity is preferable. The single rainfall obviously affect surface runoff (R=0.91)

the critical single rainfall yielding surface runoff is 22.3mm. The surface runoff and subsurface runoff respectively account for 0.58% and 99.42% of total runoff

and the forest has obvious function of protecting water resources.