Termites (Insecta, Isoptera) are ubiquitous arthropods that eflieiently digest lignocellulose into a useable energy source. This ability of termites is intimately correlated with symbiotic microbes (Tartar et al., 2009). Bacterial strains (most of them are unable to be cultured) produce cellulases and hemicellulases that hydrolyze completely lignocellulose into glucose. With the aim to convert agricultural wastes (especially straw) into value added substances, symbiotic microorganisms living in the termite gut are the potential source to supply cellulases and hemicellulases for agricultural waste conversion. In this study, the authors constructed an efficient metagenomie library of termite gut bacterial symbionts for screening genes encoding enzymes that hydrolyze lignocellulose into glucose. Metagcnomie DNA of bacterial symbionts in the termite gut was extracted by combination of the traditional extraction method and the QIAamp DNA Mini Kit of Qiagen. Then, the extracted metagcnomic DNA was partially digested with Hea111 to produce DNA segments of 3.0 - 7.0 kb. The DNA fragments were ligated with pJET1.2/blunt vector then electrotransformed into E. coli DH l0B to construct metagenomic libraries. Transformation efficiency depended on the exponential (log) phase of cell growth phase, the centrifugal speed and the electric field strength used for electroporation. Metagenomic libraries were contsructed successfully with an optimal transformation efficiency reached 3.7 x 10 exponent 9 CFU/r-tg DNA when competent cells were havested at ODbim of 0.2, the centrifugal speed was 1500 rpm and electroporated in a 0.1-cm-gap cuvette (BIO-RAD) at 12.5 KV/cm (field strength), 100 percent plasmids contained foreign DNA, 47 percent plasm ids habored DNA segments 3.0-5.0 kb.