The invention relates to a field-emission cathode device, which comprises an insulating substrate, a plurality of strip-shaped cathodes, a plurality of isolators, a plurality of strip-shaped grid meshes, a plurality of field-emission elements and a plurality of fixed layers, wherein the field-emission elements are respectively arranged at the cross positions of the strip-shaped cathodes and the strip-shaped grid meshes and electrically connected with the strip-shaped cathodes; and the fixed layers are respectively arranged on the surfaces of the strip-shaped grid meshes corresponding to the isolators, the strip-shaped grid meshes are clamped between the fixed layers and the isolators, the isolators are respectively positioned among the strip-shaped cathodes and arranged at intervals with the strip-shaped cathodes, and the field-emission cathode device further meets the following condition: D1<=D2/10, wherein the width of the isolators is defined as D1, and the distance between the central lines of the two adjacent field-emission elements is defined as D2. The invention also relates to a field-emission display adopting the field-emission cathode device.