This paper describes the design and fabrication of one kind of dichroic beam-splitter that operates in an ultra-broadband spectral range from visible to longwave infrared regions simultaneously. The use of metal-dielectric coatings makes it implement structures that transmit the visible/near infrared radiation from 0.4 to 1.05 μm and reflect infrared radiation from 1.36 to 13 μm. At the same time， the structures are designed to obtain a low linear polarization sensitivity （LPS） in the visible/near infrared region. The transmission of visible/near infrared region is more than 85% and the average reflection of infrared region is more than 90%. The LPS of the region 0.4-1.05 μm is less than 4%.