Failure modes of Mo-tip FEA were investigated in detail as a preliminary study for the application of Mo-tip FEA to the CRT electron-gun as a cold cathode. It was identified that the destruction of Mo-tip FEA was originated from reflowing of arc-current during the spot-knocking process followed by secondary arc between gate electrode and cathode substrate. In order to prevent Mo-tip FEA from destruction due to arc-current, two kinds of methods were suggested, that is one is to provide the by-pass of the reflow current and the other is to install a current limiter in the path of gate connection line.