Background:The shaking of micro-focus spot in the vertical direction is found during the energy scan experiments

such as XAFS scan.The beam position of vertical direction changes obviously with the energy.Purpose: In order to make the beam position shaking amplitude less than 1/10 of the beam size.Methods:The beam position stability of SSRF BL15U beamline is improved by using beam intensity feedback.The feedback system include beam intensity monitor of the beamline and fine adjust mechanism of pitch

2

（the pitch angle of the second crystal of the double crystal monochromator）.The feedback control of the beam position is realized by adjusting the pitch

2

to fix beam intensity at its maximum value.Results:The test results show that the vertical beam vibration below 10 Hz frequency is significantly reduced and also the beam position stability during photon energy scan is improved by more than 5 times.Conclusions:By adopting the new feedback systems

the stability of the beam spot on the specimen stage was dramatically improved which achieved the anticipated target.