Diesel Particulate Filter (DPF) is a very effective aftertreatment device to limit particulate emissions from diesel engines. As the amount of soot collected in the DPF increases, the pressure loss increases and the purification rate decreases. Therefore, DPF regeneration needs to be performed. Injected fuel into the exhaust line upstream of the Diesel Oxidation Catalyst (DOC), hydrocarbons are oxidized on the DOC, which increases the exhaust gas temperature at the DPF inlet. Also, it is necessary that the injected fuel is completely vaporized before entering the DOC, and uniformly mixed with the exhaust gases in order to make the DOC work efficiency and durably. However, ensuring complete evaporation and an optimum mixture distribution in the exhaust line are challenging. Therefore, it is important that the fuel spray feature are grasped to perform DPF regeneration effectively. The purpose of this study is the constructing a simulation model. The secondary fuel injection is classified into free spray, impingement spray, evaporation of liquid-film, and HC concentration distribution. So it is difficult to predict phenomena because each phenomenon is involved in the complex. Therefore, it is necessary that each phenomenon is evaluated in basic experiment. This report focuses on impingement spray on the wall under high temperature field and spray under the flow field. The characteristic of the impingement spray behavior is grasped by scattered light method. And, the characteristic of the gas phase of the fuel after impingement is grasped by LIEF method. Then, the liquid film shape and thickness of after impingement is revealed by LIF method. By calculating the above phenomena with the model considering the change in the impingement behavior due to the boiling state, it is possible to predict impingement spray behavior qualitatively. Also, the characteristic of spray behavior under the flow field is grasped by scattered light method.