A pixel element for field emission display includes a sealed container having a light permeable portion, an anode, a cathode, a phosphor layer formed on an end surface of the anode, and a CNT string electrically connected to and in contact with the cathode with an emission portion of the CNT string suspending. The phosphor layer is opposite to the light permeable portion, and the emission portion is corresponding to the phosphor layer. Some of CNT bundles in the CNT string are taller than and project over the adjacent CNT bundles, and each of projecting CNT bundles functions as an electron emitter. The anode, the cathode, the phosphor layer and the CNT string are enclosed in the sealed container. The luminance of the pixel element is enhanced at a relatively low voltage.