The invention provides a method for acquiring a basin coverage rate for water conversation. The method includes the steps: 1) according to four stand types, including coniferous forest, broad-leaved forest, mixed broadleaf-conifer forest and shrubbery, of a basin forest, measuring area, canopy interception rate, saturated soil water-holding capacity and the like of each stand type; 2) superposing according to respective weights to acquire coverage area, capable of realizing water conservation, of one stand type, and determining a coverage rate of each stand for water conservation; 3) fitting to acquire a basin coverage rate used for water conservation. According to the method, the forest coverage rate of a basin for water conservation is obtained by combination of years' precipitation data of the studied basin according to forest area and forest types of a surface water basin, under the guidance of the coverage rate, reasonable planning and purposeful afforestation or deforestation are performed, a water conservation function of forests is developed fully, suitable forest area of the basin is regulated in real time, blind afforestation is avoided, the contradiction of the forests and farmland is alleviated, and the method has great economic significance.