A method for realizing one card for multi-number service is disclosed, wherein the subscriber's card of the called terminal has a plurality of numbers, and the method comprises: determining the subscriber card information of the called terminal, the present activated number and the mobile switch center MSC_S based on the called number; connecting the call to the MSC_S based on the obtained routing information of the said MSC_S, and then performing the subsequent connection of the call based on the called subscriber card information. When calling a user experiencing one card for multi-number service, regardless the telephone number the user registers, the connection to the number that the user currently uses could always be realized, so as to obtain the calling or short message service targeted to the one card for multi-number service, that is, a plurality of number could be online concurrently.