The multidimensional decision is a method of making a decision for an evaluation target under the situation of many effective factors which conflict and react with each other. When the multidimensional decision is applied to trap evaluation, all of factors that reflect the quality of traps are regarded together as a whole, or several factors are integrated to a single factor that can optimally evaluate the quality of traps by muti-object calculation. The fact that it is applied in actual trap evaluation in some areas of Sichuan Basin and it is compared with the method of geological risk probability has proved that the method is of validity and applicability with advantages of simple, practical and easy operations, high resolution, less human intervention and more objective prediction result.