Raman spectroscopy was used for experimental research on D2 signal to noise ratio(SNR) under different conditions. The 32 mW Ar+ laser was injected into the Raman quartz glass cells to study the effect of grating, laser power, exposure time and the gas pressure on D2 Raman spectra SNR. D2 Raman spectral signal to noise ratio is proportional to the laser power, exposure time and gas pressure. The standard curve of the pressure and SNR for this experimental apparatus was obtained. Three sets of random samples were used to verify the formula SNR(J 2→2)=10.6×10-4p+1.271 34. When the deuterium pressure is 21 280 Pa, the relative error is 4.8%. When the pressure increases to 67 235 Pa, the relative error is down to 1.46%.