A tunable pulsed laser induced photoacoustic (PA) measurement set-up is established in the forward mode to monitor in vitro glucose concentration. A series of experiments are investigated to verify the feasibility of this set-up and scheme. Peak-to-peak values (PPVs) of several glucose aqueous solutions are recorded and averaged 512 times at each wavelength. Experimental results demonstrate that the time-resolved PA profile of glucose solutions has a good agreement with the PA theories. The characteristic wavelengths of glucose solution are determined via differential method. The root-mean-square error (RMSE) of predicted concentration reaches 3.15 mg/dl at the optimum wavelength of 1 510 nm via least square (LS) fitting algorithm.