11C micro-focused beamline is a new structural biology beamline under construction at the Pohang Accelerator Laboratory (PAL), South Korea. The aimed beam size is 5 to 20 mm, derived from the In-vacumm undulator (Period, 20 mm; Length, 1.4 m), allowing for ~10 mm protein crystallographic experiments such as data collection from micro-crystals to structural determination using the 1´1012 photons/sec X-rays. The main optical components of 11C are the Channel cut monochromator (CCM) and Kirk-patrick-Baez (KB) mirror system. Out of issues in the micro-beamline, the mirror alignment and the robust beam stability during the data collection are very important. The beam fluctuation caused by inconstant temperature could be the main problem. In this seminar, I will present the development of the 11C beamline to overcome the micro-beam unstability due to changing temperature and improve the mirror alignment for fine focusing. Finally, the beam instability reduction techniques of Photon Factory BL-17A and -1A will be discussed to exploit at 11C beamline.