Membrane proteins are proteins either embedded or located at the peripheral of the biological membrane. The functions of membrane proteins include importing/exporting ions/small molecules into/output of the cell, cellular signaling, cell-cell interactions, etc. Molecular dynamics is a powerful computational tool that can provide an atomic level description of the dynamic interactions between molecules. During my Ph.D., I have studied several membrane proteins, including a membrane transporter (BetP), three ligand-gated ion channels (AMPA receptor, Glycine receptor, and GLIC), and a membrane signaling protein (human T-cell receptor). In these projects, I have uncovered key aspects of the functional mechanism of these proteins, such as active substrate transport, ion permeation, and antigen recognition. In addition, I have developed a new computational methodology for modeling the membrane protein-detergent micelles. I strongly believe that an atomic-level understanding of membrane proteins is essential to meet the challenges in biomedicine.