The theory of transition undulator radiation was described first
then the properties of infrared and far-infrared transition undulator radiation of SSRF U9.0 were explored by the methods of analytical treatment and numerical simulation
and the influence of beam energy spread
emittance
and magnetic field errors on transition undulator radiation was given also. It was shown that the flux density of the infrared and far-infrared transition undulator radiation of the SSRF U9.0 was high (e.g.
the maximum flux density might reach 35x1013 photons/(s·mrad2· BW)
collecting angle φ =0.23mrad
and the effects of beam energy spreed
emittance and magnetic field errors on the radiation flux density were small.