A new on line titration method and device based on a new technique continuous flow titration is described. By the means of electronically controlled switching of a solenoid valve, the main component of the system, the equivalent point of the titration is easily determined. Several kinds of mixing tools were examined, whereby a self made mixing chamber with minimum volume gave best results and was therefore used in the device. The error of the titration is within 0.2% and the relative standard deviation (RSD) is below 1.2%. The results show no difference compared with a commercial device, meanwhile the new on line titration system is cheaper and fully automated and thus easy to hand and less solvent consumption. A new on line titration method and device based on a new technique continuous flow titration is described. By the means of electronically controlled switching of a solenoid valve, the main component of the system, the equivalent point of the titration is easily determined. of mixing tools were examined, whereby a self made mixing chamber with minimum volume gave best results and was therefore used in the device. The error of the titration is within 0.2% and the relative standard deviation (RSD) is below 1.2%. show no difference compared with a commercial device, meanwhile the new on line titration system is cheaper and fully automated and thus easy to hand and less solvent consumption.