PbSrSe layers and PbSe/PbSrSe multiple quantum well (MQW) structures have been grown on BaF2 (111) substrates by molecular beam epitaxy. The lattice constant of the PbSrSe alloy was determined by x-ray diffraction, and both the refractive index and absorption edge of the PbSrSe alloy with Sr composition up to 0.23 were obtained from Fourier transform infrared transmission spectra at room temperature. MQW structures exhibit strong photoluminescence (PL) in the 3-5 mu m wavelength range ar room temperature, The PL intensity decreases monotonically with increasing temperature below 230 K.