Abstract: Effects of mulching weights and materials on dynamic of phosphorus contents in rhizospheric soil of poplar plantation were investigated in this paper. The results showed that the contents of total P increased with the increasing of mulching materials. The contents of total P after the treatment with 2.5, 5.0, 7.5 kg/m2 were 10.77%, 13.85%and 52.31%higher than that in control respectively. There were little differences among different mulching materials, but the contents of total P mulching with them were higher than that of the control. The contents of available P in rhizospheric soil obviously increased after mulching. The contents of available P rised as mulching weights increased. Mulching materials had remarkable effects on the contents of available P. C. nepalensis and L cylindrical vat. major were superior to Q. fabric and P. aquilinum var. latiuscukum. The effects of mulching materials on dynamic of phosphorus contents in rhizospheric soil were similar to mulching weights. It was found that the contents of total P and available P decreased from April to July, then increased from July to December after biological mulching.