Radio frequency identification (RFID) technology is one of the promising technologies enabling the realization of the Internet of Things. However, the current major application is limited to using its identification ability. The number of applications will be increased if we can enable RFID technology to have the capability of accurate localization. In this paper, we propose a new sensor deployment method for improving the passive RFID localization accuracy. The proposed method integrates computer vision technology while employing a genetic algorithm to find the appropriate locations to deploy RFID reader antennas. The proposed method was applied to a fingerprinting-based indoor localization system. The result showed that the localization accuracy can be effectively improved by selecting the appropriate deployment locations of RFID reader antennas.