Fractal dimension is often used to characterize the distribution of complexity fractures. However, the existing fractal dimension calculation method can only obtain one fractal dimension for a specific fracture network, which cannot accurately describe the complexity hydraulic fractures with strong heterogeneity. This work considers the actual distribution of complex hydraulic fractures in stimulated reservoir area, calculate fractal dimensions of complex hydraulic fractures at different regions. A new quantitative model is established to describes the distribution of heterogeneous fractal dimensions (QM-FD), and obtains the relationship between fractal dimensions and fracture locations. Combined with the heterogeneous fractal dimensions for complex hydraulic fractures, the porosity/permeability/compressibility of complex fractures is determined, and a more general distribution of flow capacity parameters of complex fractures is obtained. A conceptual reservoir model with complex hydraulic fractures is given in the work, and the fractal dimension distribution is described with the proposed approach, then the permeability is calculated with the fractal dimensions. The permeability calculated by heterogeneous fractal dimensions and the actual permeability is compared, and results show that the fitting rate between the calculated permeability and the real value is higher than 93%. The proposed approach is used in four typical reservoirs with complex hydraulic fractures, the fractal dimensions and equivalent permeability is calculated and compared with that from conventional fractal model. The conventional fractal model is poor in dealing with the description of complex hydraulic fractures with non-monotonic changes, and the fitting rate is below then 60%. While the fitting rate of the equivalent permeability calculated by the heterogeneous fractal dimensions in this work and the actual permeability is higher than 92%. The calculation approach of heterogeneous fractal dimensions proposed in the work can be applied to parameter characterization of complex fractures, which provides effective help for flow simulation and productivity prediction of unconventional reservoirs.