In order to study the mechanical properties of cement soil subjected to the coupling effect of chloride salt solution and dry wet cycles, unconfined compression test, ultrasonic test, scanning electron microscope(SEM) test and X ray diffraction(XRD) test were performed. The change rules of mass loss rate, relative wave velocity, peak stress, residual stress, deformation modulus and microstructure characteristics of cement soil were investigated. The results show that with increasing chloride salt concentration and the number of dry wet cycles, the internal microstructure of cement soil becomes more loose, and the mass loss rate increases, but the P wave velocity decreases. The stress strain curve of cement soil subjected to the coupling effect of chloride salt and dry wet cycles can be divided into compaction phase, elastic plastic phase, failure phase and residual phase. The peak stress and residual stress of cement soil comply with the exponential decline law. Compared with those before the wet dry cycle, the peak stress, residual stress and deformation modulus subjected to 28 wet dry cycles in water, 45, 180, 300g/L NaCl solutions decrease by 4879%, 5771% and 4933%, 5263%, 4876% and 5437%, 5688%, 5970% and 575%, 5789%, 5771% and 6567%, respectively. And the residual stress is 20%40% of the peak stress.