Abstract: In order to dispense with operator's inspection work, a device for detecting and rejecting filter rods containing spliced tow ends was designed by adopting high-sensitivity photoelectric sensing technology. Tow splice is identified dependent on the levels of the variation of tow opening width, which is converted into the switch signal of diffuse reflection photoelectric sensor; and activates the rejecting valve through a PLC to the targeted filter rods. The filter rods of 2 750 Pa were tested on a KDF4 filter rod maker, the results showed that the rejection accuracy rate for tow splice contained filter rods reached 100%, the average draw resistance of rejected filter rods was 2 346 Pa, which was beyond the acceptable range of (2 750±245) Pa required by technological standards. This technology provides a support for promoting the automation of filter rod makers.