Uncertainties in ecological data are well known, because of measurement errors, complex behaviors of biological organisms, unpredictable environment, and the complex interactions among them. It is challenge to account for these uncertainties in analysis of ecological data. Hierarchical Bayesian modeling provides a framework that accounts for these sources of uncertainties. Meanwhile the model structure and parameter uncertainty can be evaluated. In the talk, I will introduce basic concepts of Bayesian inference and hierarchical modeling. A case study on mark-recapture data will be presented. I will introduce briefly another more complex example on spatial species community which I am currently working on.