The experiment was conducted during two successive seasons (2015 and 2016) on Balady orange trees (Citrus sinensis) which divided in two groups. The first group was sprayed with potassium sulphate (48%) in the orchard at three times sequential (March, June and August) and the second group was sprayed with water (control). Orange fruits of both treatments were collected in maturity stage and dipped in salicylic acid (SA) at 4mM/l in laboratory. The purpose of this investigation is studying the effect of SA and K on orange fruits quality during storage at room temperature (13+2 C°). Some physical and chemical properties of fruits were estimated every 10 days till 50 days (the end of storage) such as weight loss %, juice content%, acidity%, total soluble solids% (TSS), TSS/ acid ratio and ascorbic acid during both seasons. The results illustrated that, SA had a positive effect on fruit quality of the fruits treated with SA single or combined with potassium sulphate