Taiwan Photon Source (TPS) is a most important project for the Taiwan government; from 2007 to 2013 the total budget amounts to more thaan NT6,885 million. It will set up a synchrotron storage ring (electron energy 3.3 GeV, circumference 518 m, low emittance) that will provide one of the world's brightest synchrotron sources of x-rays. This paper focuses on the stability of the TPS power supply and the current ripple of the quadrupole and sextupole magnets, with an analysis and measurement of the response character of the power supply in relation to the impact for magnet loading.