The　main　objective　of　this　paper　is　to　identify　the　corticomuscular　responses　of　card-grabbing　and　obtain　a　unified　structural　model.　The　unified　structural　model　reveals　the　key　characteristics　shared　across　healthy　subjects,　quantifies　human　cortical　sensorimotor　function.　Electroencephalogram　(EEG)　and　electromyographic　(EMG)　signals　of　ten　subjects　was　recorded　during　card-grabbing.　Multiple　forward　regression　orthogonal　least　squares　(MFROLS)　algorithm　was　used　to　detect　a　uniform　model　structure　of　the　subjects,　and　a　nonlinear　autoregressive　moving　average　model　with　exogenous　inputs　(NARMAX)　corticomuscular　model　was　established　to　analyze　the　human　sensorimotor　system　in　time-frequency　domain.　The　corticomuscular　model　identified　by　MFROLS　algorithm　has　both　linear　and　nonlinear　model　terms,　and　achieved　0.9780　variance　accounted　for　when　implementing　a　one-step-ahead　prediction.　The　peaking　effect　around　0,　12,　20　Hz　was　observed　by　frequency　domain　analysis.　Using　MFROLS　algorithm　can　detect　the　common　characteristics　of　corticomuscular　responses　during　card-grabbing.　The　measured　corticomuscular　responses　are　the　integration　of　sensorimotor　feedback　signals　and　motor　commands　in　the　cerebral　cortex,　and　the　human　sensorimotor　system　has　the　characteristics　of　nonlinear　harmonics　at　specific　coupling　frequencies.　©　2022　IEEE.