The present study aimed to investigate the antioxidant, analgesic and anti inflammatory properties of astaxanthin extracted from a new Algerian strain of Haematococcus pluvialis (H. pluvialis). Antioxidant activity of astaxanthin was evaluated with FRAP, β-carotene bleaching and FTC methods. Analgesic activity was determined by acetic acid-induced abdominal constrictions model. Anti-inflammatory activity was determined using In vitro, In vivo and In silico methods. Results showed that iron reducing capacity astaxanthin evaluated with FRAP test was about 3.7 times higher than that recorded with the standard, ascorbic acid. The β carotene bleaching test showed that this carotenoid was more effective on inhibition of the lipid peroxidation than BHA one. The lipid peroxidation inhibition rate of astaxanthin was twice higher than that of the ascorbic acid. Oral administration of astaxanthin in mice showed its ability to reduce abdominal constrictions induced by acetic acid. The efficacy of astaxanthin in preventing protein denaturation and erythrocytes membrane injury was important. It inactivated the cyclooxygenase 2 and exhibited a significant inhibition against carrageenan induced inflammation. Moreover, there was no evidence of toxicity in mice given the algal extract. This suggests that the astaxanthin from H. pluvialis has interesting biological properties and could be used safely in food and pharmaceutical industries.