By comparison and analysis, dynamic characteristics were studied of phosphorus input through atmospheric deposition and output with streams, rivers and seepage water, and their effects on soil total phosphorus and available phosphorus in forest soils under different types of forests, i.e. Korean pine plantation, larixlarix olgensis plantation, natural Korean pine and linden mixed forest, natural Korean pine and Betula costataBetula costata mixed forest, natural secondary birch forest, within a temperate forest ecosystem in the Dailing Liangshui National Nature Reserve, Heilongjiang Province. Results show that the annual atmospheric phosphorus deposition with rainfall was at 0.888 kg/hm^-2 ; phosphorus concentration was higher in July in throughfall in all the forests except Korean pine plantation than in the rain from the sky; it was lower in July and August in percolating water through soil A horizon in natural Korean pine and Betula costataBetula costata mixed forest, natural secondary birch forest and Korean pine plantation, than in rainfall inside the forests, which suggests that the topsoils fixed a part of the phosphorus brought in with thoughfall, and it was higher in Stream 1, Stream 2 and the Langshui River, all inside the forest ecosystem of the natural reserve, and the Yongcui River outside the natural reserve than in bulk precipitation and throughfall, showing an order of bulk precipitation < throughfall < streams < Langshui River < percolating water through Soil layer A < Yongcui River, which indicates that a part of the phosphorus in the soil is lost, flowing with surface runoff and leaching into streams out of the forest ecosystem and finally pooled into the river, causing phosphorus enrichment in the streams and rivers. TP in A₀ horizon of the soil in the natural Korean pine and linden mixed forest was negatively related, but TP in B horizon of the soil in the Korean pine plantation and available P in A₀ horizon of the soil in the birch plantation were both positively related, to atmospheric phosphorus deposition and phosphorus output from the forest water system.