Fourier transform infrared spectroscopy (FTIR) was used to measure the spectroscopic information of isoprene. Using Gaussian 03 program under density functional theory (DFT), the reaction mechanism of OH- isoprene adducts were studies with abinitio methods at the B3LYP/6-31G(d,p) level of theory for optimized geomethies and frequency calculations. Results show that the experimental results agreed well with the theoretical values. The pathways involved in the reaction between OH- and isoprene were found and the methods to block this key reaction pathway in principle were discussed.