Abstract: The performance of the BOB (Blender-on-Board system) composite additives developed by Dalian lubricating Oil R&D Institute for special cylinder oil blending was tested. Some simulation methods of differential scanning calorimetry, Caterpillar Micro Oxidation Test, hot tube tester, panel coker tester, spread-ability tester, SRV, SEM，were carried out to evaluate the anti-oxidation performance, deposit control, spread-ability and friction resistance under the conditions of low dosage of BOB additives. The results reveal that the optimal BOB additives show better overall performance but less anti-oxidation, comparing with foreign reference.