After COMS launch on 27 June, KOSC(Korea Ocean Satellite Center) have been trying to check GOCI(Geostationary Ocean Color Imager) physical status and performance. The fi rst test will be GOCI’s data download and ground receiving test. Next, the checking & decision for overall status of GOCI is very important not only for GOCI mission capabilities but also for reimbursement of GOCI insurance if there is some partial failure in the GOCI H/W system, i.e. our user requirements. Before gathering image; solar power supply, attitude control, internal temperature, moving parts control, optical alignment, optical contamination, and other GOCI system performance checkswill be done. During the image acquisition test (from 13 July), we will check also reasonable sensor (high & low) gain values test for ocean, land and cloud for a nominal operation of GOCI. The next step will be pointing accuracy of GOCI target for each slots (16 slots will be taken for a scene) Main checking points are ; if there will besmall deviation between slot to slot overlapped area, center pointing accuracy, mosaic capability for slot to slot, geometrical correction, the number of dead or bad CMOS pixels, radiometric function test for all pixel, and SNR values for each bands, and in-orbit MTF check will be done. Finally, the downloaded data will be inputted intoGDPS(GOCI Data Processing System) for level-2 data production. All GOCI general status will be mentioned in this presentation.