In an attempt to construct superior Trichoderma harzianum isolates for improvement β-glucosidase productivity, induction of mutants and protoplast fusion techniques were applied. After application of UV irradiation and Ethyl methane sulfonate ( EMS), 461 isolates were obtained, out of them 99 after UV application and 362 isolates after EMS treatments. These isolates were tested for their CMCase and β-glucosidase productivities in comparison with the original strain. Five  isolates (tow after UV application and three after EMS treatments) were selected on the basis of their highly productivity of both enzymes to be treated with colchicine (0.1% and 0.2%) as a second step of mutation induction. After colchicine treatments, 191 isolates were obtained, out of them 40 isolates after treating  the wild type strain, 70 isolates after treating the two UV induced-mutants with colchicine and 81 isolates after treating the three EMS induced-mutants with colchicine .These isolates were tested for their CMCase and β-glucosidase productivities. One isolate (D1/4) proved to be the highest producer for the  two enzymes, since it produced 160% and 186% CMCase and β-glucosidase, respectively, more than the original strain. Twenty isolates were selected to be tested for their resistance or sensitivity against four antifungal agents. Out of them four isolates were selected on the basis of their response for antifungal agents and their productivities of two enzymes to be introduced into intraspecific protoplast fusion experiments using two different  methods ( PEG and electrofusion) . Three crosses were carried out among four selected isolates. The results showed that the numbers of fusants obtained after electrofusion were more than those obtained after PEG method. In addition, highly productivities of CMCase and β- glucosidase were obtained after electrofusion in three crosses. Highest DNA content and also highest amounts of CMCase and  β- glucosidase were obtained after EMS-treatments followed by colchicine application