Ecological water requirement and ecological water shortage of (Zanthoxylum bungeanum var. dintanensis) forestland under different mulching plantations were studied in typical Karst valley area. The results showed that there were 375 % of the rocks exposed rate in the 100 m2 plot, its acreage was only 625 m2. Range of soil moisture was 153—185 m3 in the period of growth and development, but it was 156—206 m3 and 152—192 m3 by litter mulching and stone mulching respectively, their increasing rates were 669 % and 432 % respectively, which range average of increase and change of litter mulching was best. Transpiration quantitative was 91962 7 mm in the period of growth and development, in which transpiration quantitative of showleaf stage. Their relations: maturity stage＞floweringfruiting stage＞showleaf stage. In order to ensure top yields and quality of Z. bungeanum var. dintanensis, management should be reinforced of soil moisture of floweringfruiting stage and maturity stage. Potential and reality evapotranspiration of forestland was 51518 3 m3, 54950 1 m3 respectively in the period of growth and development, but their evapotranspiration decreased, in which stone mulching conspicuous decreased. Ecological water requirement of forestland was 61479 4 m3 in the period of growth and development, but it was 58424 2 m3 and 46000 1 m3 respectively by litter mulching and stone mulching. Ecological water shortage decreases and water shortage didn’t appear by different mulching in the period of maturity. Overall, ecological water requirement of forestland was related with soil moisture, evapotranspiration of forestland and transpiration of plants. Water shortage was lest by litter mulching, and plant would exhibit stronger drought resistance in the growth period. Therefore, afforestation should select lither mulching in karst area, but the relationship between the thickness of mulching and changes of water requirement deserves further study.