The invention relates to a testing device and a testing method for combustion characteristics of liquid fuels of an engine. The testing device comprises a combustion reactor, a heating system, a temperature control system, a combustion injecting system, an ignition system, a shooting system, a scavenging system, a control system and the like, wherein the control system is used for carrying out start-stop operation on all other systems; the combustion reactor adopts a quartz glass three-mouth flask; heating equipment is an electrothermal furnace; temperature control is realized by the temperature sensor; a servo motor pushes a spiral injector to inject fuel; a pulse type igniter 7 is used for performing fuel ignition; a high-speed camera is used for shooting; an air pump is used for scavenging. The control system controls the operations such as heating, fuel injection, ignition, shooting and scavenging according to the characteristics of fuel, the temperature in the combustion reactor and the concentration of waste gases and further the test of the combustion characteristics of engine fuels is realized. By means of the testing method, the test of the combustion characteristics of easily-ignitable fuels and easy compression ignition fuels and the like can be realized.