Carbon dioxide (CO2) gas sensor using surface acoustic wave (SAW) device based on Zinc oxide (ZnO) was developed and fabricated in this paper. The center frequency of SAW device is 203.528 MHz. The input and two output interdigital transducers (IDT) apodized by Morlet wavelet function can improve the side lobe rejection compared with uniform IDT. The ZnO film sensitive to CO2 gas was fabricated in measurement acoustic track of SAW device. Experiments results confirm that the CO2 gas sensor using SAW device based on ZnO film has good response characteristics to different concentrations CO2 gas. Furthermore, the CO2 gas sensor using SAW device based on ZnO film has good stability and linearity.