CDMA cellular mobile communication service needs to offer good quality of services (QoS) and coverage for new and sophisticated power control to achieve high capacity. In this paper, in order to efficient cell sector and to improve the Ec/Io of the pilot channel in CDMA mobile communication systems, we analyze and compare the wide-beam trisector cell(WBTC) with the narrow-beam trisector cell(NBTC) as a method for cell sectorization. The NBTC method was compared with the WBTC method, using the results of both a theoretical analysis and a simulation, in order to examine its effectiveness and validity. As a result, we confirm that efficient cell sector method to minimize interference from adjacent base stations and to increase cell coverage.