The clarification of Moroccan Valencia orange juice performed by ultrafiltration (UF) using flat sheet polysulfone (PS) membrane with molecular weight cut off 20 kDa. The freshly squeezed juice, after a depectinization step, was submitted to an UF process. In experimental tests performed according to the total recycle mode for study the effect of the operating conditions on the permeate flux and quality. The clarified juice was produced according to the batch concentration mode working in optimal operating and fluid dynamic conditions. The quality of the samples coming from the UF process was evaluated in terms of: total soluble solids (TSS), color, clarity, total antioxidant activity (TAA), total flavonoids content (TFC), ascorbic acid (AA), and total phenolics content (TPC). The clarified orange juice was highly close to the initial juice except for suspended solids (SS) and pectin content which were totally concentrated in the retentate. In the permeate of the UF process a low reduction of TPC (12.4%), TAA (13.52%), TFC (13.41%) and AA (7.86%) were observed with respect to the initial juice.