Abstract: China Superconducting wiggler, or WLS (wavelength shifter), generates short  wavelength SR. WLS effects and modeling are studied. This paper focuses on 2 creative pieces of the work: estimation of the WLS effects, giving the biggest 1st and 3rd order Taylorintegrals; precise modeling of the linear effect with 3 edge-angled sterms in field piecewisely constant magnets．