The invention aims to provide a photovoltaic absorption model for a single medium-voltage feeder in a medium-voltage distribution network, which can determine the capacity of a single medium-voltage feeder in a medium-voltage distribution network of a photovoltaic power generation system through an algorithm after defining specific constraints. In order to solve the technical problem, the photovoltaic absorption model for the single medium-voltage feeder in the medium-voltage distribution network is implemented according to the following technical scheme: the establishment mode is that the installed capacity of the maximum distributed power supply to which the single medium-voltage feeder can access is solved under the premise of meeting node voltage and operation constraints; and the process comprises the steps of obtaining power balance constraints, node voltage constraints, substation bus voltage range constraints and line capacity constraints, and building a specific model. Compared with the prior art, the position and capacity of photovoltaic power generation are given so as to calculate the voltage distribution and system short-circuit current under various load levels by adopting a heuristic algorithm through model construction, and finally an upper limit of the capacity is obtained.