Abstract A V-shaped spacroscopic cell (V-cell) was constructed using two CaF2 optical plates for FTIR light transparent measurements in the range of 4000-1000 cm-1. The spectrum of ethanol was characterized with the standard spectra, excellent fitting was achieved with a bottom-width correction method. The principle of the V-cell was discussed, giving equations for the data interpretation. It shows that the V-cell is an auto-focus type spectroscopic cell, which can effectively avoid absorption saturation with amplifications for weak absorption bands. The V-cell design is simple and effective, easy to operate, suitable for applications in liquid samples with high absorption bands, willing to have broad application prospects.