The RF receiver for the CDMA mobile communication BTS system according to the present invention realizes the system with an analog down-converter to process multiple FA's and generate IF signals of 70 MHz having a bandwidth corresponding to the multiple FA's with a mixer, and a digital down-converter to digitally process the respective FA's through A/D conversion of the IF signals of 70 MHz, allowing simple multi-FA(3FA)-based expansion. Also, the system needs only one analog down-converter for simultaneously processing 3 FA's and one digital down-converter for digitally processing the IF signals from the analog down-converter by FA's to down-convert the IF signals to baseband signals, thereby reducing the size of the system and hence the hardware cost. The system can be implemented with higher stability by digitally processing the down-conversion of the analog IF signals of multiple FA's to the baseband signals.