The time and space resolved optical emission spectroscopy (OES) of optical glass plasma produced by nanosecond laser pulse (wavelength of 355 nm and pulse width of 5 ns) in air are investigated in this paper. Results show that OES is mainly consisted of continuous spectrum at the early stage of plasma expansion (within the first 200 ns) and the continuous spectrum weakens gradually while the line spectrum becomes dominating. The spectral intensity decreases when the ablated pulse energy increases more than 35 mJ for the existence of the plasma shielding. The wavelength red-shift of Si I 390.6 nm, which has a second order exponential decay with delay time, has been found based on the time-resolved emission spectroscopy.