The reservoir classification study is important work for managing scientifically the reservoir and raising the effects of oilfield development．In view of the reservoir characteristic parameters，the reservoirs are classified by cluster analysis method on the basis of the similar relationship of the reservoir features，which overcomes the influence of human factors．According to the attribute value of each category．the discriminant functions are established．The multibank discriminant methods are applied to calculate the probability of the standard type for unknown reservoir,and then the similar degree with the standard one is decided．Thus the type of the unknown reservoir is determined accurately． The result shows that the use of these two kinds of mathematical methods can classify and manage the reservoir scientifically．