As a crucial biomolecule of life, protein has diverse three-dimensional structural and functional properties, typically with various $\alpha$-helix and $\beta$-fold ratios. Its structure in living organisms provides important information for the study of normal or pathological physiological processes. And the nanopore technology, as a novel single-molecule sensor, has been used extensively in protein molecular detection and structural identification, because of its advantages such as label-free and easy operation. Here, we use solid-state nanopores to detect two kinds of structural proteins. The results show that since different proteins cause different blocking current signals when passing through solid-state nanopores, so we confirmed that solid-state nanopores enable protein characterization and the $\beta$-fold-rich proteins have more structural possibilities.