Taking Lanzhou city as an example, the characteristics of groung motion parameter microzoning in cities which are located in the yellow river valley in northweastern China are studied. The importance of input data for calculating the parameter during strong earthquakes is demonstrated, the relationships between the ground motion parameter microzoning and the local cite conditions, the essences of soil layers, the geomorphological condition are analysed. According to the site conditions and calculating results the urban part of Lanzhou city is divided into 3 regions, and the parameters of each region for aseismic design are also illustrated.