Forests are main carbon pools in terrestrial ecosystems. Accurate estimation of forest biomass could improve estimation of the magnitude and distribution of carbon sinks. Precipitation-driven changes affect forest biomass, but the effects of precipitation on large-scale forest biomass patterns are still poorly understood in China. Here, biomass allocation patterns of eight typical forest types across China were studied to determine their biomass allocation patterns across broad precipitation. With increase of mean annual precipitation (MAP), stem, branch, leaf and shoot biomasses showed significant changes in seven of the eight forest types. Root biomass and MAP only had a significant relationship with four of the eight forest types. There was significant relationship between forest biomass and MAP in six of the eight forest types. Root: shoot ratios had a significant decline in four of the eight forest types. Root biomass was less limited by precipitation than shoot biomass. Precipitation affects biomass distribution patterns differentially in forest type, and the effects of future precipitation change on biomass are complex.