Cover Story：Antibody (also named as an immunoglobulin, Ig), a most important macromolecule for immune response in human body, has been developed as macromolecular drug to treat the cancer and immune diseases. Understanding of antibody three-dimensional (3D) structure and fluctuation could be an important step for further understanding and controlling the antibody pharmacological function. However, the study is limited by antibody flexible structure. In this paper, we reviewed the current research progresses on structural study of human IgG1 antibody conducted by our recently developed individual-particle electron tomography (IPET) method. The review includes the sample preparation method, basic logic of image processing strategy, 3D analysis and its application in antibody-drug conjunction and antibody structural fluctuation. We also discussed the strengths and weakness of the technique.