Currently, two planar superconducting undulators (SCU) and one helical superconducting undulator are in operation at the APS storage ring. For all these cryostats, the magnets are cooled independently from the beam chamber and a magnet/mold is cooled by LHe in the Helium channel which is cooled by cryocoolers. Based on these design and operational experiences, a new APSU-SCU cryostat is being developed. FEA model of SCU cryostats is developed which includes all the heat source and cooling powers provided by cryocooler load maps. In this talk, I will present a method to calculate an excess cooling power first, then this method is bench marked by FEA model of the 1st generation (SCU1) cryostat. Secondly, FEA model of the 2nd generation (HSCU) cryostat is presented and calculation and measurement are compared. Finally, current status of the FEA model of APS-SCU cryostat is presented.