Abstract: According to reflected characteristic of sprouting quantity, average height and diameter to disturbance intensity and frequency, three different disturbance types of strong, middle and poor grade Broussonetia papyrifera sprouting population were compartmentalized. By samples, study on biomass construction of B. papyrifera’s sprouting population with different age in the Karst region and set up biomass model by relative growth under different disturbed degree. By this model, the author researched the biomass construction and distribution of sprouting population under three different disturbed degree, and estimated biomass of B. papyrifera population in the community. The results showed that the disturbance is the main factor to influence the producing of spouting, the biomass construction and allocation of sprouting population is different because of the disturbed degree. The disturbed degree showed strong disturbance>middle disturbance>poor disturbance