Abstract: A pulsed electric field device for selective removal of target ions at the front of the ion detector for a time-of-flight mass spectrometer was introduced. The pulsed electric field device had three grid meshes: MCP grid mesh, pulse grid mesh and ACCE grid mesh. The effective removal of the non-target ions was achieved by adjusting the pulse voltage and its width on pulse grid mesh to impede the non-target ions reaching the ion detector, in order to reduce the consumption of ion detector and prolong the life time of the ion detector. The experimental results showed that the pulsed electric field device could remove one or more interval ions through changing pulse voltage to adjust the removal rate and changing pulse width to adjust the removal span range. Except for spectral signal oscillations caused by the rising and falling edges of the pulse for neighbor ions, the device could effectively remove the non-target ions, and kept the other target ions stable. This specific ion removal method can provide an easy way to improve the existing TOF MS instruments.