In this talk,I will first introduce experimental approaches we used in my laboratoryto characterize protein structure and to visualize protein dynamics.A protein exists in an ensemble of conformations in solution.Inter-conversion between these conformations allows the protein to perform its designed functions.SolutionNMRand other biophysical methods mostly measure the ensembleaveragedparameters.So the inverse problem in visualizing protein dynamics is how to find a best combination of protein conformations that can satisfy the observed parameters.I will give a few examples,and discuss problems we have encountered.