[en] A continuous spectrum of synchrotron radiation in the hard x-ray region, 5-20 keV, is necessary for the special demand of users, but the high radiation power in that continuous spectrum adversely affects the design of optical components in the beam line. A compromise between photon flux and radiation power of insertion devices should hence be considered. An algorithm and code for spectrum optimization was hence developed using program Mathematica. A wiggler-like undulator with a continuous spectrum was investigated with this code. An optimization algorithm for continuous spectra in the energy range 5-20 keV is presented, and features of the wiggler-like undulator with a continuous spectrum are discussed herein.