Method for reckoning precipitation in return period through calculation point without effective meteorological observation data

The invention discloses a method for reckoning precipitation in a return period at a quasi-calculation point without effective meteorological observation data, and the method comprises the steps: carrying out the random sampling of all available rainfall data of a region around the quasi-calculation point based on the extraction probability of an observation sample through a random number generator, and carrying out the repeated sampling from the data of a surrounding observation station point, thereby generating a space synthesis sequence sample set; according to the sampling extraction probability, factors such as the time sequence length of each observation station sample and the altitude and the separation distance of a to-be-calculated point and an observation station are considered. Carrying out cross test comparison through the precipitation in the return period obtained by fitting long sequence observation data of adjacent stations, selecting a probability distribution function with the minimum averag