The COVID-19 pandemic caused by SARS-CoV-2 has precipitated a global public health emergency, necessitating the urgent development of rapid and accurate virus detection methods. Compared with the current single-signal detection methods commonly used, dual-mode detection has inherent self-verification and self-correction functions and is expected to provide more reliable and interference-resistant detection results. In this work, a rapid approach for SARS-CoV-2 detection was developed using an electrochemical and colorimetric immunosensor based on a NiFe layered double hydroxide (LDH) loaded with silver citrate (NiFe-LDH@AgCit). The electrochemical sensor is capable of measuring the electrical signal of the transition from Ag to Ag⁺ in the presence of SARS-CoV-2. At the same time, the color reaction of 3,3′,5,5′-tetramethylbenzidine with ⋅OH can be used to build a colorimetric sensor. In electrochemical and colorimetric sensing systems, the linear detection ranges were 0.0005–10 and 0.001–10 ng mL⁻¹, respectively. The corresponding limits of detection reached as low as 0.167 and 0.333 pg mL⁻¹, respectively. In addition, the dual-signal sensor has been favorably used for the detection of SARS-CoV-2 in human serum, and the recovery ranges were 99.0 %–101.6 % and 100.6 %–104.5 %, respectively. In conclusion, the proposed dual-signal sensing technique offers novel insights for the prompt diagnosis of virus-related illnesses, which has wide application prospects.