Studies on protein molecular devices have attracted a lot of interests, because they play important roles in human daily life. The rapid development of scanning probe microscope (SPM) technology provides enabling tools to study protein on molecular level. The structure, mechanical and electrical/electrochemical properties of redox proteins are the important issues in related device studies, and corresponding advanced topics such as current-voltage curve, force-distance curve and chemical potential control of SPM are reviewed in this paper. Therefore, these parameters might be instructive for further application of SPM in related fields.