Nucleic Acid Testing (NAT) has become the “gold standard” for diagnosing SARS-Cov-2 infections in China. However, NATis affected by factors such as the disease course, specimen collection, the testing process, which are prone to false positives and missed diagnoses. The detection of SARS-Cov-2-specific IgM and IgG antibodies in serum has been used as an auxiliary method for SARS-Cov-2 detection, which can remedy the “false negative” shortcomings of NATand improve the positive rate of detection. A low-cost portable device is proposed in the paper for SARS-Cov-2 IgM and IgG antibody quantitative measurement. The device comprises a CPU signal processing module, a light source driver module, a multi-spectral detection module, a power supply module, and a display storage and communication module. Fluorescence immunochromatography technology combines the IgM and IgG antibodies in the sample to be tested with the quantum dots and trapsthem on the T line of the test strip. The light source driver module with a square-wave modulation is utilized to simulate the ultraviolet LED. Consequently the emitted ultraviolet light illuminates the T line and C line of the immunofluorescence chromatography test strip through a roof-shaped optical system. The quantum dot marker is excited by the light source to emit red fluorescence, and then the red fluorescence is captured by the multi-spectral detection module passing through the narrow-band filter. Then, the multi-spectral signal is subjected to the FFT transformation in the CPU to obtain its spectral feature. The ratio of the feature of the signal band and the reference band is applied for normalization processing to eliminate the background and environmental interference signal and to calculate the fluorescence intensity. The final detection results are displayed on the UI and uploaded to the server database, and data sharing and information management can be realized through a remote query on the computer. Therefore, the contents of IgM and IgG antibodies are determined according to the calibration coefficient of the feature ratio. Repeated experiments have been carried out using normal human serum samples as measurement reagents. The experimental results show that the CV value ranges from 0 to 8.30%, among which the CV value of the T line is only 3.45%. Two types of solution containing IgG and IgM antibodies are used to prepare a series of sample solutions with different mass concentrations using the gradient dilution method for the linearity experiment.The result is fitted by the least square method with a fitting coefficient of 0.997 5. Finally, the serum antibody test of the SARS-Cov-2 vaccine shows that the positive detection rate is up to 75%. The device has a tiny structure, low power consumption, simple operation and good performance. Therefore, it can be applied as an auxiliary means to improve the positive detection rate of SARS-Cov-2 infection effectively.