The invention provides a new technology for enhancing the ion utilization efficiency in the ion migration tube ionization region, and particularly provides a pulse field ion migration tube. A pulse varying electric field is applied to the ionization region and the migration region of the ion migration tube so that the electric field in the ionization region can be enhanced and the electric field in the migration region can be reduced at the moment of opening of the ion gate, all the ions in the ionization region can be injected into the migration region and spatial focusing compression is performed on the ion groups by using the difference of the electric field intensity of the ionization region and the migration region and thus the sensitivity of the ion migration tube can be greatly enhanced and the ion migration tube is enabled to have great resolution capacity.