Abstract In order to effectively improve the economic benefits of large-scale fracturing of the single well in tight reservoirs, avoid investment risks and raise development effects, research on the forecast means of large-scale multi-branch fracturing capacity is carried out. Large-scale fracturing has high costs and high investment risks, it is necessary to conduct relatively accurate forecast for the capacity after fracturing to reduce investment risks. On the basis of the single-well capacity data of 78 large-scale fracturing wells that have been put into production in the Hailar Basin, the geological, development and engineering factors affecting capacity were deeply analyzed and summarized. According to different applicable conditions, the theoretical derivation and polynomial linear regression methods are used; two different capacity forecast models of tight reservoir are given. These two forecast models are used, the error of capacity forecast results after fracturing is less than 15%, and the accuracy can meet the actual application requirements of the mine, therefore, this forecast method provides a powerful technical support for the promotion of large-scale fracturing technology and reducing economic risks.