DECDIS (Satellite Deep Charging &Discharging Simulator) has been  designed and fabricated by our lab, it is the first proper facility in  our country, to research on internal charging on satellites. A Sr90/Y90  beta emitting source and a EK-100-FL electron gun are designed in one  vacuum chamber, they can be used to test internal charging and measure  conductivity of dielectrics respectively. Temperature control is  provided by a set of semiconductor heaters, and surface potential  measurements are taken by Trek341B. This facility can be used to develop  design approaches that may reduce the risk posed by internal charging,  for our country’s upgrading middle and high earth orbit satellites.