Solar air collectors are commonly used in a variety of domestic and industrial fields. The simple design and low maintenance cost are among their advantages compared to other solar collectors. However, the main challenge of this type of collector is the low heat transfer coefficient. In this work, the effect of different designs of the absorber plate (waved and V corrugated modification) on the thermal performances, the heat exchange effectiveness and the air outlet temperature of a Double-Pass Parallel-Flow air solar collector was investigated under the solar radiation of Marrakech-Morocco in a clear day and for three different mass flows rates (0.008 kg s -1 , 0.012 kg s -1 and 0.016 kg s -1 ). The numerical study was done using Computational Fluid Dynamics (CFD) by the mean of ANSYS Fluent 16.0. The obtained results showed that the V corrugated modification is the most efficient one with efficiency equal to 76.92 % and 87.97 % under the lowest and highest mass flow, respectively.