In order to resolve soil water deficiency in Pingshan County , Heibei Province , the application of the technology of water-holding agent was studied.In this experiment , acacia was used as an example of forest species and absolute random design was used to investigate the effect of water-holding regent on growing items (height of plant and diameter of stem) and ecological item (photosynthesis) and the effect of waterholding agent on soil water content and soil nutrients.Results showed that the direct applying model of mixing soil with water-holding agent was better than that of mixing soil with water-holding agent absorbing water beforehand.The diameter of stem and the height of plant were promoted by 19.70 %～34.0- % and 41.41 %～48.04 % by this applying mode , respectively.Soil fertility level was improved after - year application (Total N was increased by 41.80 %; available P , by 130.77 %; available K, -4.86 %; and Microelements , by 41.37 %～67-.16 %) .64 g/ plant was the best amount of application and water-remaining effect was still significant after applying water-holding agent 3 years later.