The invention discloses a large photovoltaic power generation cluster photovoltaic curtailment power estimation method based on nearest distance clustering. Photovoltaic clusters are located in photovoltaic power stations; and the photovoltaic power stations are divided into benchmarking photovoltaic power stations and non-benchmarking photovoltaic power stations. The estimation method comprises the following steps: as for the non-benchmarking photovoltaic power stations, a corresponding photovoltaic power station is found according to the nearest distance rule, and the corresponding photovoltaic power station is added to the corresponding benchmarking photovoltaic power station cluster; each subclass of the cluster is a benchmarking photovoltaic power station; the start-up capacity of each benchmarking photovoltaic power station is calculated; the real-time start-up capacity of each photovoltaic cluster at each t minutes obtained in the first step is calculated; theoretical output of the photovoltaic cluster at each t minutes is calculated; whether statistical ending time arrives is judged; and the photovoltaic curtailment power of the entire photovoltaic cluster during a time period from start to end is calculated.