Abstract: In order to solve the problem that the Penman-Monteith formula is limited in the calculation of reference evapotranspiration (ET₀) in the area without meteorological stations, Monte Carlo numerical simulation is used to simulate the static and dynamic numerical fluctuation probability of air temperature and humidity, net radiation and wind speed required to calculate ET₀ respectively. The results showed that net radiation is the main influencing factor affects ET₀ fluctuation, and air temperature, humidity and wind speed are secondary factors. By comparing the monthly average and real-time meteorological data of temperature, humidity, and wind speed using the 2022 meteorological data from Xinjie Taigemiao mining area, it was found that the total value of the two data and the difference in quarterly data can be controlled within 1%. This article preliminarily analyzes that using monthly averages instead of real-time meteorological data of secondary influencing factors in areas lacking meteorological stations can meet production and application needs while reducing the cost of setting up meteorological stations.