With shallow ore deposit reducing day by day, it is more difficult for geological prospecting and the geological prospecting effect is becoming less. Faced with the above problem, this paper puts forward a set of technical methods of 3D geological modeling with large and medium scale at key metallogenic belt. By three-dimensional geological modeling, accurate and imaginal 3D geological models can be established, the 3D spatial distribution and the relationship between the various geological bodies can be expressed, so as to carry out geological research and prospecting prediction more effectively.The methods had been put into practice in Tongguan district in Shanxi province , Gejiu district in Yunnan provice, Yulong porphyry copper deposit in Tibet (Xizang) and North China craton sedimentary-metamorphic iron deposit ,and a very good achievement was obtained which provided a choice program for upcoming 3D geological mapping in China.