A new noncentrosymmetric compound, Na2Cd7B8O20, has been synthesized by solid-state reaction for the first time. The crystal structure has been determined from single crystal X-ray diffraction data. The compound crystallizes in the orthorhombic space group Fdd2 with a = 51.5597(7) angstrom, b = 58.6920(8) angstrom and c = 3.381 angstrom. The crystal structure is composed of CdOn (n = 6, 7), Na-CdOn (n = 5, 6) NaOn (n = 4, 6) polyhedra, B3O7 and BO3 units. The B3O7 unit is built up of three BO3 groups via corner-sharing, rarely found in borate compounds. The IR spectrum, the optical diffuse reflectance spectrum and nonlinear optical properties of Na2Cd7B8O20 are reported.