Relating to a device and method for production and injection of a tracer, the invention provides a device and method for production and injection of a PLIF (planar laser induced fluorescence) flow field diagnosis tracer. During high-time and high-spatial resolution quantitative measurement of mixed fuel gas by a PLIF diagnostic technique, experimental accuracy can be affected due to the incapability of accurate determination of mixed steam's temperature, pressure and concentration. According to the invention, a generation tank is communicated with a gas mixing tank through a first gas transmission pipeline, the generation tank is equipped with a first thermocouple, and the gas mixing tank is equipped with a second thermocouple. The method provided by the invention consists of: step 1. formation of pure tracer steam; step 2. adjustment of mixed gas concentration; step 3. pressurization and dilution of diluent gas in the gas mixing tank according to an ideal gas state equation PV=nRT, thus obtaining a mixed gas meeting the experiment required concentration of A, temperature of T and pressure of P; and step 4. injection of the mixed gas. The device and the method provided by the invention are used for the process of tracer production and injection into an experimental field.