An ionization vacuum gauge includes a linear cathode, an anode, and an ion collector. The linear cathode, the anode, and the ion collector are concentrically aligned and arranged from center to outer, in that order. The linear cathode includes a linear base and a field emission film deposited coating on the linear base. The ionization vacuum gauge with low power consumption can be used in a high vacuum system and/or some special vacuum system that is sensitive to heat and light. Such a gauge can be used to determine, simply yet accurately, pressures at relatively high vacuum levels.