The grating spectrometer is used to measure the spatially resolved emission spectrum of plasma in single pulsed laser ablation of bronze-bonded diamond grinding wheel. The electronic temperature of plasma in single pulsed laser ablation is 5220 K by calculation. The electron density is about 0.5×1016-1.8×1016 cm-3 at the range of 0-0.35 mm away from the grinding wheel surface. The spatial distribution model of plasma concentration and the dynamic equation of isothermal expansion are built. The simulation results show that the maximum isothermal expansion speed of plasma appears approximately at 25 ns during the single pulse time. The maximum plasma concentration of 1.8943×1016 cm-3 appears at 0.05 mm away from the grinding wheel surface, and the plasma shielding effect is so small that it can be ignored in the actual process. The experimental results have the same order of magnitude with the numerical simulation results, which verifies the correctness of the plasma physical model. The research results offer guidance to the optimization of pulsed laser ablation process.