Abstract: Impact of urbanization on precipitation has been confirmed in multiple studies, but very little is knwon about impact of precipitation at different stages of urbanization in Jinan city, in particular, therefore impact of urbanization on precipitation during flood period was investigated with land use and precipitation data from 1985-2022． The characteristics of land use change was analyzed, response patterns of rainfall to underlying surface imperviousness was explored, effects of imperviousness on different precipitation was studied． Data indicate that the urbanization process in Jinan experienced four stages, with the period from 1995 to 2000 witnessing the most substantial increase in impervious surfaces at an average rate of 114.77 km²·a⁻¹． With an imperviousness rate of > 26%, rainfall enhancement coefficient became greater than 1.0, but at 1.10 when imperiousness was > 43%, and potentially 1.20 when imperiousness rate was > 60%． The expansion of impervious surfaces notably increased the occurrence of light rainfall．