In a multi-channel resistance-based gas sensor system, the multi-channel array includes gas sensor channels respectively connected to resistive type gas sensors. The pre-processing unit selects a current mode, a resistance mode, or an external resistance mode, analyzes a sensing value obtained from any one of the gas sensor channels based on the selected mode and outputs a voltage value corresponding thereto. The analog-to-digital converter (ADC) converts the voltage value to digital data. The control unit controls the pre-processing unit to execute one of the current mode for analyzing a sensing value smaller than or equal to a preset first resistance value, the external resistance mode for analyzing a sensing value greater than or equal to a preset second resistance value greater than the preset first resistance value and the resistance mode for analyzing a sensing value between the preset resistance first value and the preset second resistance value.