A simple method for the prediction of drag coefficient of artificial fishreef results from an application of momentum theorem to the arbitary control volume. The artificial fishreef applied to the calculation is the Great-Reef type model. Drag coefficient was determined numerically from momentum balance using the mean velocity distribution by wind tunnel testing. From these estimations, it was found that in the case of present model 225A drag coefficient C_D nearly equals to 0.92,while a conventional value evaluated to artificial fishreef constructed with the porous face and frame was too high.