Multiphase reactors and multiphase flow systems have found extensive related to energy, environmental, chemicals, petroleum and variety of products processes. Multiphase flow reactors are complex due to the intricate interactions and reactions among difference phases. Therefore, sophisticated techniques that integrate measurements in a novel way of various hydrodynamics and transport parameters and their integration with kinetics are required to quantify and visualize these systems to provide benchmarking data for validating CFD and models. These advances should provide the mechanistic frame work to properly scale up the results from lab to commercial scales.In our laboratory, various types of multiphase systems such as slurry/basket reactors and packed bed reactors under high temperature and high pressure for various industrial and environmental processes have been studied by developing advanced measurement techniques and validating CFD simulations which enable process intensification and facilitating the implementation of new mechanistic scale-up methodologies. In general, these techniques can be classified into two categories: radioisotope techniques and non-radioisotopes techniques. The radioisotope techniques include radioactive particle tracking (RPT), dual source gamma ray tomography (DSCT), gamma ray densitometry (GRD) for 3D flow field, velocity and turbulent parameters, phases distribution and flow pattern identification measurements. The non-radioisotope techniques include 4-point optical probe for bubble dynamics, optical probes for gas-solid dynamics, optical probe for local mass transfer, optical probe for local liquid and gas velocities, holdup and their time series distribution in packed beds, gas tracer technique for global mass transfer, heat transfer probe, pressure transducers, and others.