In this paper, We analyze and inspect the problem of our country PSTN subscriber telephone number and suggest the ISDN/PSTN subsciber numbering plan in the future. Expecially, when you eastablish plan to change present telephone number system to ISDN telephone number system, public goverment and public office which has many calls have to be given a same number that many people want and being easy rememberance thoughout the country. Therefore we think that it is saving hours and reduce lost calls. As concrete action of convert plan it must be made consistent numbering plan when the numbering reorganization is carried out in Korea before T-time. If a partial is not carried out, it should be given when the telephone number is newly-organized or the big buliding and goverment and public office eastablich RSS individually. At that time chaos will be minimized.