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Agrometeorological disasters severely impact agriculture in Heilongjiang Province. Flood is one of the main agrometeorological disasters in Heilongjiang Province. The temporal change in flood events in Heilongjiang Province from 1986 to 2015 was studied using Mann-Kendall and Morlet wavelet methods, respectively. The results of Mann-Kendall analysis showed that the disaster rates of flood gradually stabilized from 1986 to 2015 with a confidence level of 99%. The Morlet wavelet variance analysis revealed that disaster rates of flood changed periodically at time scales of 3a, 7a and 18a in Heilongjiang Province during 1986-2015. The dominant period of the variation of flood disaster rate was about 18a over the past 30 years. The flood disaster rates were indicated in a positive phase during the period of 2016-2020 by the fitting curve of Morlet wavelet analysis. The annual average flood disaster indexes of single station, during 1986-2015 years were calculated, according to the precipitation data at 31 stations in Heilongjiang Province and the GIS software was used to analyze the spatial change in flood disasters in Heilongjiang Province from 1986-2015. The results demonstrated that the southwest area of Heilongjiang Province was highly hazardous region of flood. The flood indices in the north part of Songnen Plain and southwest of Heilongjiang Province presented the increment trends.