CS-x (x = 1, 2, 4, 6) nanoparticles have been successfully prepared by simple hydrothermal method combined with calcination process, and the calcination time is adjusted to optimize micro-structure characterization for their enhanced NO-sensing. The techniques of XRD, Raman, SEM, TEM, TGA, DSC, BET, and XPS are used to study their phase structure, micro-morphology, thermal decomposition process and surface states, then the possible gas-sensitive mechanism is analyzed. Results show that the typical CS-2 sensor has the maximum response of 130–50 ppm NO at 90 ℃, the short response/recovery time of 40/45 s, and the low detection limit of 0.1 ppm (1.18). It also has the reliable NO selectivity against to other interfering gases, good repeatability and high stability. Its enhanced NO-sensing performance may be due to the optimization of pore structure by adjusting the calcination process based on particles adhesion and mass transfer, which increases the pore size and specific surface area that could provide the channel and active sites for gas diffusion and adsorption, thus further promoting the gas-sensing reaction. The experimental methods and ideas of pore structure regulation provide a new way for the design of high-performance sensitive materials.