The method of optical detection to test polyacrylamide solution was developed which took advantage of TU-1901/1900 double-beam UV-Vis spectrophotometer and IRPrestige-21 FT-IR Spectrometer to measure the transmitted spectrum of polyacrylamide solution in the range of 5~600 mg·L-1 concentration. The spectrum characteristics and inverse analysis their concentrations of polyacrylamide solution within the wavelength of 190~900 nm and 400~4 000 cm-1 were investigated. The results show that there are strong absorption of polyacrylamide solution in 200~300 nm, 400~920 cm-1, 2986~3 684 cm-1 and the transmittances of solution with different concentrations have linear relationship at 220 nm and 2 623 cm-1; the maximum calculation error to inverse the unknown concentrations successively are 6.98%, 2.34% and 0.79%, when inversion calculation uses 2, 3, 4 measured values in ultraviolet band.