Due to global climate change, forest structure and function have changed significantly. Usually forests are regarded as sinks rather than sources of nutrients. However, in the cold temperate zone, flowing the long-term accumulation of these nutrients on the forest floor could potentially result in forests becoming sources rather than sinks of nutrients. Hence, what effect does the forest have on the transport of chemical elements in precipitation and runoff? It is an important scientific question. To analyse the variability in cold temperate zone larch forest ecosystem chemical transport, we used chemical and instrument analysis methods to monitor the water quality of precipitation and runoff that flowed through the forest system. The results showed that the K, Na, Mn, Zn and Fe chemical element content of precipitation in the Greater Xing'an Mountain region had significant variability in 1997, 2008 and 2015. The Mg, K, Na and Cu contents of runoff differed significantly in 1997, 2008 and 2015. The chemical element content had obvious variability after precipitation flowed through the forest ecosystem of Greater Xing'an Mountain. This showed that the forest ecosystem of Greater Xing'an Mountain had a significant influence on water quality. Therefore, the forest ecosystem in the Greater Xing'an Mountain have increased the retention of nutrients, which is conducive to forest growth. But it will also increase the iron et al. in the water body, which affects the water quality.