As a flatten technology of traditional color television (kinescope), Field Emission Display has been attached much importance at home and abroad, and has great got progress. Field Electron Emission is called Field Emission for short. It's the physics foundation of Field Emission electronics components, and Fied Emission test technology is the technology foundation of studying field cathode materials and field electronic components.The relationship of Field Emission current and electrical field strength is the main job of Field Emission test. It needs to measure nA level current in high voltage condition, and the measurement and collection can be easily disturbed by noises.There is no proper Field Emission test system in home and broad.This paper designs a Field Emission system that is able to measure range from 10nA to 1mA, namely 5 amount levels'current, using the high DC power which is existed in our laboratory, and the system fulfils the Field Emission test demands.The paper has done the following jobs:1. Considering the characteristics of field emission current, using logarithm amplifier to measure the current. The solution is verified by the experiment.2. Using LPC2148 Micro-Control Unit to control AD conversion and data collection, and designed hardware circuit and software program.3. Using IrDA technology to realize the measurement of weak current signal in high voltage condition.4. Designes U disk using the on-chip Flash memory of LPC2148, and also study the USB protocol and debugs the USB interface in order to upload the data of U disk to PC. So that it is convenient for following data process.The paper summarizes the design of Field Emission test system at last, and given the shortages of the system, the following work, and somewhere desired to be improved. The paper has done the jobs of design of hardware and software, PCB layout, weld circuit board, machine assemblage, system debugging and measurement experiment. The innovation of the paper is using the IrDA technology to realize the measurement of field emission current signal in high voltage condition.