Abstract: The optical performance of trichromatic beam splitters developed for DF laser appli-cations as shared- aperture components is presented. In this paper,we have discussed thesubstrate of splitter optical elements meeting spliting performance,the selection of coating materi-als,multilayer film design and techniques, and the performance results measured.The experimen-tal results of R>99.6% at 3.8μm wavelength, the average transmittanee of more than 0.75 at thelong wavelength 8～14μm and the average transmittanee of more than 0.50 at the CCD responseregoin for the trichromatic splitting film with uncoated back surface of ZnSe substrate are ob-tained. The environmental stability of the samples are examined.