As a result of the low level of geological prospecting and the few sites of known mineral deposits in the northwest of Heilongjiang province, weight evidence method which is based on statistics is not suitable for this area. Therefore, Whith combined weight evidence method with an “expert knowledge system” which is built on the basis of knowledge achieved in basic geology, regular of regional mineralization and characteristics of gold mineralization, we establish a mineral resources quantitative evaluation system of mineral resouces based on expert weight evidence method. Applying this system to evaluate gold mineral in the northwest of Heilongjiang achieves good results and lays a foundation to further look for minerals in this area.