We report the development and calibration of a built optical magnetic twisting cytometry (OMTC) system. The development includes hardware assembly and software integration. The system has been calibrated in terms of its noise characteristics. The results demonstrated that in current experimental condition the system performed satisfactorily with negligible noise level. The ASM cell also exhibited stiffening in response to mechanical stimulation due to continuous twisting of beads on the cell surface, providing a useful technique for studying the role of ASM cell mechanics in pathogenesis of respiratory disease such as asthma.