Abstract: The evolution of an orogenic belt may involve two phases: the orogenic phase and mountain building phase. Regional geological survey in China has long centered on the geological survey of the orogenic phase, with emphasis on the study of the basic geological features in a region. On the other hand, the geological survey of the mountain building phase has long been neglected. This is precisely the problem that should be discussed in the present situation of “enlarging the service scope of regional geological survey”. The main aspects for the regional geological survey of the mountain building phase of the orogenic belt are: （1） the process and characteristics of the uplift of the orogenic belt; （2） environmental effect of the mountain uplift; （3） recent tectonic movement and geological hazards in the orogenic belt. On the basis of the 1∶250 000 regional surveys of the Dongeiconag Lake Sheet and Xinghai County Sheet of the orogenic belt in the East Kunlun Mountains, the authors discuss the mountain building processes and environmental change of the orogenic belt.