Abstract: This paper proposes total supply capability curve (TSC curve) and total accommodation capability curve (TAC curve), which can completely evaluate the capability of active distribution network (ADN) under various loads and distributed generation (DG) distributions, and guide the further exploitation of system potential. Firstly, the security region, security boundary and TSC curve of passive distribution network are introduced. Secondly, the DC power flow model of ADN security region is given. ADN has load growth and load reduction criticality, as well as DG growth and DG reduction criticality. Furthurmore, the upper/lower load boundary and the upper/lower DG boundary are defined. Aiming at the shortcomings of DC power flow model, the voltage verification and correction method of boundary points is given. Then, the models of TSC curves and TAC curves are established. The upper TSC curve describes the capability range of ADN to supply load, that is, the TSC curve of passive network. The lower TSC curve describes the load needed for the priority of DG accommodation. The upper TAC curve describes the capability range of ADN to accommodate DG; the lower TSC curve describes the DG needed for the priority of load supply. Finally, a simple case and IEEE 33-node test system are used to verify the concepts and models. It is found that the TSC and TAC curves are not completely symmetrical, and their duality principle is revealed in this paper. Compared with the existing calculation methods of accommodation capacity, the application values of curves are shown.