The determination of interwell permeability can be used to reservoir description and plane heterogeneity evaluation，which is of vital importance to the oilfield development decision making. The conventional approach for calculating interwell permeability is dynamic testing method. Because of the complex operation process and excessive cost，its application has been limited. To solve this problem，the relationship between interwell permeability and injection allocation coefficients was established based on hydropower similarity principle. Combined with Capacitance-Resistance Model（CRM）that enables estimation of injection allocation coefficients，a novel method was proposed for calculating the interwell permeability using injection and production data. The method was validated by numerical conceptual models，and was further applied to E07 well group in south Bozhong 25 oilfield. The results show that the estimated interwell permeability in direction of oil well E18 reaches the maximum value，which matches the fastest frontal movement of waterflood in that direction by tracer testing. In addition，the estimated value 5 192×10-3 μm2 in E18 direction is basically consistent with the interpretation value 5 616×10- 3 μm2 by tracer testing. The method extends the application range of CRM from injection allocation coefficients estimation to interwell permeability estimation，which provides a rapid and efficient tool for reservoir plane heterogeneity research.