The volatility and randomness of photovoltaic (PV) output will affect the security and reliability of power system dispatching operation. In order to accurately simulate the PV output over a long time scale, this paper proposes a time-series power simulation model of PV output based on Markov chain. Firstly, a photovoltaic output model is established, and the uncertainty and regularity characteristics of output are analyzed. Then, considering the output relationship between adjacent days of the year on the basis of the first-order Markov chain model, the historical data is sampled in a rolling way with 10 days as a sampling interval based on the season and weather factors, and a multi-state transition probability matrix is established, and then the annual time series output model is constructed; Finally, based on the output data and the annual historical meteorological monitoring data of a PV plant, the simulation of the annual output is conducted and the results are compared with the traditional methods. The example results verify the effectiveness of the proposed method, which shows that the method can simulate the PV output under the influence of season and weather, and is consistent with the historical actual situation.