Based on the annual maximum diurnal rainfall data from 12 metrological stations over Honghe of Yunnan Province in the recent 48 to 58 years, the extreme value distribution of annual maximum diurnal rainfall is fitted with the PearsonⅢ distribution, Gumbel distribution, and logarithmic distribution, and their extreme values at various reappearance periods are calculated by the best probability distribution. The results show that these three probability distribution models can fit well the distribution of annual maximum diurnal rainfall; the fitting results with Gumbel distribution are the best for 7 stations, PearsonⅢ distribution for 4 stations, and lognormal distribution for 1 stations, and they all reached the standards of significance test. For various given reappearance periods, the distribution characteristics of annual maximum diurnal rainfall over Honghe are very similar, and maximum and minimum centers are consistent, higher in South and lower in north.