This study was conducted to evaluate the effect of seed bio-priming on the salinity tolerance of pepper (Capsicum annuum L. var Chargui). The pretreatment was carried out by the aqueous extracts of Padina pavonica (at 60 g/L) and Jania rubens (at 80 g/L). The tests were carried out at 0, 3 and 12 g/L of salt for germination and 0 and 3 g/L for the growth which was conducted in hydroponics. Seeds were soaked in these extracts, and two batches were considered (treated and un-treated (control)). The results showed that the effect of salt was harmful on the integrity of the membrane, respiration, and mineral (Potasium and Posphorus) compositions of pepper. Nevertheless, it increased proline, total soluble sugars, sodium and secondary metabolites accumulation. the pretreatment showed that the best tolerance to salt stress in pepper was due to a better oxidative status demonstrated by the reduction of oxidative damage (reduction of leakage of electrolytes and MDA content), accumulation of secondary metabolites, at better hydration resulting from more efficient osmotic adjustment due to the accumulation of osmotica (proline, total soluble sugar, potassium and phosphorus) and an increase in metabolic activity by the improving breathing. This technique of biological pretreatment may submit with agriculture an interesting tool to increase plant tolerance to salt stress and to find an alternative to any chemical use.