Stimulated reservoir volume is an important parameter of the development for shale gas and oil reservoirs. During the production of multi-stage hydraulic fracturing, kinds of problems may be countered. For example, there are many overlap fracturing zones among stages, and complex fracture networks may be created. The processing flow is proposed to estimate the stimulated reservoir volume of multi-stage fracturing. At first, DBSCAN algorithm is used to eliminate the outliers and divide the complex distribution into several sub-distributions for calculating the SRV of the complex distribution. Then, MVEE algorithm is used to calculate SRV based on microseismic event distributions. At last, the volume of overlap zone is calculated by using affine transformation with the parameters of ellipsoid. So, the overall stimulated reservoir volume can be obtained. Two groups of field data are used to evaluate the proposed method. The processing results confirm the validity of the proposed method.