To understand the eco-hydrological functions of litter,the water absorbing and releasing speed, the dynamics of holding water, and the effects of environmental factors on holding water were studied. A plantation of larch (Larix principi-rupprechtii) in the small watershed of Diediegou in north side of Liupan M ountains, Ningxia Hui Autonomous Region w as selected as research stands. Results show ed that the equation for water absorbing speed of litter and its immersed time was y= 38. 206lnx+ 133.38(R²=0.952 1) and the equation for water releasing speed of litter and its immersed time, y= 339.1e^{-0.000 3x}(R²=0.880 6).The water-holding ability of the larch litter was as high as 415.97% of the dry weight. According to the observation on water dynamic process of litter across a grow thseason, the water content of litter decreased markedly in the case of no rainfall for a long time, but increased after rainfall as a result of water-absorption by litter. The drying-up and wetting dynamic process occurred continuously with raining. By correlation analysis, the water amount held in litter w as significantly and positively related with rainfall depth, but negatively related with temperature, solar radiation, wind speed, atmosphere w ater potential,and vapor pressure deficiency (P<0.01).