A transient 3-D mathematical model for double-pass solar collector with porous media in the lower channel has been developed. Numerical simulations model based on setting mass, momentum and energy balances on finite volumes method are carried out. The governing equations inside the two channels, together with the energy equation in the absorber, insulating and glass cover walls were solved iteratively in a segregated manner. Effects of porosity (70-90 %), mass flow (0.03-0.07 kg/s), solar intensity (514-714 W/m2) and spacing glassabsorber-insulation (7-10 cm) on the dynamic and thermal behaviors of the double pass solar collector with and without porous media have been discussed. The study concluded that the presence of the porous media at the bottom of the absorber is the best configuration and allow increasing the outlet temperature.