Research purposes: With issusing the licenses of the third generation mobile communication (3G)system,the testphase of the 3G system hasbeen finished, and 3G system goes to commercialuseage. Meanwhile, the 3G system has to be introduced intometro for communication. However, as the space in themetro underground station is narrow,irregular in shape, the scheme to combinemultiple networks into one network isused for the 3G system. Throgh analysis and comparison of severaloptional schemes of introducing the 3G system intometro, thispaperoffers and introducesone appropriate scheme forproviding the reference to introducing the 3G system intometro.