In order to find out different material evidences in criminal spot, multi-band lamp house was adopted to achieve all kinds of field traces. Multi-band lamp house system can utilize interference cut-off filters of different performances to output different wave-band beams. In order to find body fluids on clothes and other traces, the high transmittance rectangular wave between 450~520 nm waveband with low-cost and high-quality was prepared through the interference filter combination method. The electronic beam depositing method with the aid of ion deposition system was also adopted based on the interference filter theory and film design software during the preparation. It is demanded that transmissivity in pass wave is more than 99%, the other wave-band is less than 0.2%, and its slope is less than 3%.