A new technique to determine the telescope reference point and system delay (Multi-target calibration) in the KSP-SLR system is proposed. The concept is to estimate the position of the reference point and the system delay simultaneously, using ranging data from five terrestrial targets which consist of three pillars and two bench marks. The telescope reference point is difficult to identify precisely and may not be so stable in the future compared with the terrestrial targets. So it is necessary to monitor the displacement of the reference point frequently. The technique enables us to monitor for a long period the changes in position regarding the telescope reference point, and to precisely calibrate the satellite laser ranging data using the estimated system delay as well. Our results, which used terrestrial ranging data from Aug. 24 to Sep.10 1998 in the Koganei site, showed that the estimated positions of the telescope reference point were stable within 1.4 mm RMS, that the horizontal components of the positions were almost equal to the surveyed values, and that the vertical components slightly shifted upward. The results also showed that the estimated two-way system delays were stable within 10 ps RMS.