Polyster fibers have special importance in textile industry as a result of having desirable mechanical and chemical characteristics such as high durability, great dimensional stability, wrinkle-leess, and low production costs. However, it has certain disadvantage such as lack of hydrophilicity and build-up of electrostatic charge. Thus, in this project in order to improve the hydrophilicity of polyester,surface coating was used by sodium alginate and the effect of the surface modification process with ultraviolet radiation with ozone gas was evaluated on increasing the efficiency and Fastness properties of the coating. The using possibility of alginate coating was evaluated as a bed to keep of kelp active substance. To evaluate the effect of surface modification treatment on the fabric and also the durability of alginate on it, some tests were performed such as moisture absorption, Vertical wicking height, time of water drop absorption, measurement of the drop contact angle, Strength, and rubbing and washing fastness. FTIR spectrum, SEM images and staining of methylene blue were used to study the structural changes occurred on samples. The results showed improvements in Wettability properties of the samples as a result of surface modification by UV/Ozone. It is confirmed that increase in staining of methylene blue along with FTIR spectrum, have increased functional groups like carboxylic acid. SEM images have demonstrated a certain amount of corrosion and microscopic pores on the surface that increases roughness and surface functional groups, which will improve Wettability properties of the textiles. Comparisons between dry and wet methods in radiation different times of 15, 30 and 45 minutes, The results indicated that 30 minutes of UV/Ozone radiation with wet method, is the most appropriate method for surface modification, with a short wetting time and minimum damage to mass fiber. The results obtained from Rubbing and washing fastness of the coated samples with alginate, confirmed the use of UV/Ozone surface modification methods for increasing of alginate stability on the surface. The results acquired from alginate coating under different methods and concentrations, showed that the most appropriate and most efficient of way is the conventional method of pad-dry-cure with concentration of 0.5 W/V of alginate. After examining abrasion stability of the kelp active substance on the finished surface, it was concluded that alginate can be a proper material as a bed to keep the active substance. Keywords: Polyester, Surface modification,UV/Ozone, Coating, Sodium Alginate, the active substance, Kelp.