Abstract: Aiming at the shortcomings of existing online cigarette inspection system,a new online cigarette inspection system was developed to improve the rejection accuracy for defective cigarettes.The system used standard PC and commercial I/O hardware as a hardware platform,adopted RTX to extend Windows and integrate online cigarette inspection system with OPC server.It real-timely detected and analyzed every cigarette and accurately rejected defective cigarettes.By the networking ability of PC,the system offered information for the demand of enterprise through OPC standard interface.The application results indicated that the system ran stably and was easy in setting and maintenance,whose missing rate and false rate in rejecting air leak or loose end cigarette were less than 0.2% or 0.1%,respectively.