Silkworm (Bombyx mori) is a highly domesticated and economically important insect which is the primary producer of silk. Apart from silk production Bombyx mori had a lot of applications in biological and scientific research. Hemolymph is the circulating fluid of insects, similar to mammalian blood, which moves through the open circulatory system, directly bathing the organs and tissues. The mulberry silkworm, Bombyx mori, has been raised for more than 5000 years in Asian countries, and is a major economic resource for many families. In the present investigation an attempt was made to study the effect of different concentrations (1, 3 and 5%) of Spirulina as supplementary diet on the silk production and biochemical profile of haemolymph of silk Bombyx mori L. In the study biochemical parameters such as glucose, protein, cholesterol, ALT and AST were found to be significantly increased in haemolymph that had been fed on Spirulina supplemented. The increased content of this biochemical parameters had positive relationship to physiological function of the insects.