Natural fractures are important reservoir spaces and effective seepage channels for metamorphic buried hill reservoirs. For metamorphic rock reservoirs an interconnected network of multi-scale fractures is key to forming high quality contiguous reservoirs and achieving high, stable reservoir productivity. In this study, the power law distribution of fractures is established based on detailed characterization of multi-scale fractures using image log, core, thin section and SEM data. The contribution of malti-scale fractures to reservior storage is clarified, and the spatial pattern of fracture network and its impact on productivity is analyzed. According to the results, fracture systems of different scales in the study area show similar change patterns, i.e., the increase of fracture intensity follows the power law with the decrease of fracture size. In tight reservoirs, large and well connected macroscopic fractures provide important permeability, but their contribution to porosity is limited due to low fracture density; whereas microfractures with high fracture density can provide important reservoir space, but they mainly play the role of connecting matrix pores due to their small aperture and limited connectivity. According to spatial combination of multi-scale fractures, five types of fracture networks are recognized. Among them, the multi-scale/high-density/multi-set combination type and large-scale/medium-density/multi-set type networks can form large-scale continuous high-quality reservoirs and achieve high, stable production, while small-scale/high-density/multi-set type and large-scale/low-density/multi-set type networks require hydraulic fracturing to achieve stable production; small-scale/low-density/single-set type fracture network can not improve tight reservoir due to difficulty of obtaining industrial oil flow.