This paper reports on comparison and validation of JP-8 and its surrogates. Jet-A POSF-4658, S-8 POSF-4734 and Sasol IPK POSF-5642 are chosen as referenced target jet fuels. All surrogates of three targeted jet fuels are mixed among six pure chemical compounds which are n-dodecane, n-decane, iso-octane, iso-cetane, decalin, and toluene. Before validating surrogates in an optically accessible engine, all surrogates were tested in Ignition Quality Tester (IQT) to match Ignition Delay (ID) with targeted jet fuels. After optimization of mixture composition of surrogates, all six fuels are tested in an optically accessible engine under a wide range of pressure and temperature conditions. Low temperature combustion characteristic and reaction behavior were analyzed with 2-D broadband chemiluminescence, and high temperature combustion characteristic were investigated with OH chemiluminescence. Including two optical measurements, cylinder pressure over the engine cycle were studied to validating global combustion behavior. Exploration of chemical and physical characteristics of surrogates for Jet-A and S-8, they well represented their target jet fuels under the conditions examined in an optical engine. Surrogate for Sasol-IPK well represented low temperature ignition delay of target fuel, matching of combustion phasing required shift in Start of Injection (SOI).