This article proposes an algorithm for high-lift system detent signal, which converts the sensor signal generated by flap/slat control lever into the detent command signal of the high lift system computer. Compared with the traditional algorithm, this one has two advantages. The first is to add the confirmation step of the signal validity in the calculation of flap/slat control lever detent signal, which can avoid generating the invalid detent signal when the flap/slat control lever goes though the invalid signal zone for a short time, and then impact the subsequent calculation of the detent command signal. The second is to add the algorithm step of setting the two computers as the master-slave configuration and voting calculation in the detent command algorithm, which can avoid detent command inconsistency among different lanes due to the delay of signal transmission, thus causing the flap slow or slat slow issue. This algorithm can make the final output detent command signal of the four lanes correct and consistent, and has been verified by experiments that its robustness is strong, which is helpful for the design of civil aircraft high lift system.