This paper is an interdisciplinary study. The core idea is to observe the combustion process by means of nondestructive testing. A new combustion chamber detection method is explored through low cost and non-polluting nuclear imaging. In this research, the fluid imaging of a combustion chamber was obtained by Positron Emission Tomography (PET). In experiment, the chamber is constructed in PET scanner. The relevant engineering details and operations are described. The kerosene was labeled by F-18 tracer. The PET detected the entire combustion flow field of the chamber. In results and analysis, this paper showed the PET images and used Computational Fluid Dynamics (CFD) to analyze the causes of feature formation in PET images. By Correlation calculation between PET images and various parameter distributions of burner fluid, the correlation results showed that the image features had a close relationship with Turbulent Viscosity (TV) distribution.Through this experiment, PET imaging is proved to be feasible and effective to trace diffusion flame fluid.