Effects of cumulus precipitation and artificial seeding on the rainfall and raindrop size are simulated in Gutian area, Fujian province in terms of a one-and-a-half-dimensional time-dependent icebearing cumulus model. It is shown that 120 mimutes after the ice crystals increase at the upper layer of clouds upon seeding, the total rainfall will increase by 0.5mm and its relative increment by 7.1%. The mechanism of the increased rainfalI is also discussed in the paper. In addition, experiments are made in the AgI seeding amount for the comparison of the raindrop size and rain intensity in this area.