Beauvericin, a cyclohexadepsipeptide-possessing natural product with synergistic antifungal, insecticidal, and cytotoxic activitie. Total DNA was extracted from B. bassiana Egyptian isolate. The integrity of total DNA was estimated by ethidium bromide re, taq DNA polymerase and (Forward and Reverse) primers directly which designed to amplify the beauvericin gene. The nucleotide sequence of the PCR-amplified fragment for the beauvericin gene of B. bassiana EG-isolate was done to determine the relationship with other B. bassiana isolates registered in Gen Bank, and was aligned by using DNAMAN program (Wisconsin, Madison, USA) with another three B. bassiana  isolates. The predict numbers of amino acids were produced from translation of beauvericin gene nucleotide sequence were 211 amino acids. A phylogenetic tree of beauvericin from B. bassiana Eg. isolate revealed 100% a high degree of similarity to beauvericin of B. bassiana non ribosomal cyclo depsipeptide synthetase, (Accession no.  AC130655), 94.3% and 94.8% to beauvericin of B. bassiana biosynthetic  protein (Accession no.  ADO 60131) and beauvericin of B. bassiana biosynthetic protein, (Accession no.  AFJ44691) respectively. While, the insecticidal effect of toxins crude extraction was studied in this wake . Toxins crude extraction due to isolate of B. bassiana investigated against 3^rd inster larvae of S. littoralis. After 4 days, the percentage of mortality  were 51.00%, 57.50%, 79.00% and 96.50% in the concentrations 25, 50, 75 and 100%, respectively.