It’s a starting point of career for the students who have passed the college entrance examination to choose a major. Major Selection System can check the real personality trait and then help select the matching major based on the data obtained. This study improves data mining algorithms by putting the plane vector reference system into it and digs out the implied relevance in the sample set to build the measure system. In this way, the inaccuracy of previous expert systems can almost be avoided so that the major can match the students more objectively. Experiments show that the precision and efficiency of the algorithms are almost satisfactory.