By means of the supercell plane wave method, investigated the effect of the third component material as the introduced defect on the band structure of two-dimension two-component phononic crystal (PC). It shows that: when the filling fraction of defect rods changes, defect bands can appear in the primary band gap whose position and width had a minor change; the frequency of the defect states/bands are mainly affected by the third material′s physical parameters; When the filling fraction of normal rods changes, defect bands appear in the primary band gap whose position and width had also a major change, and all the defect states are localization. Therefore, adding proper third material as linear defects to the two-component system with wider band gap where defect bands will fall into, some special filter guided states will be formed. This characteristic has a very important significance for acoustic /elastic wave propagating and new acoustic applications.