The modern scientific and technical revolution is responsible for increasing interest and impetus in the search for materials possessing specific and desired properties. Today, the transition metal diborides (TMB2) are of great interest because they have been found to possess unique physical and chemical properties. As an important physical quantity, the Debye temperature is closely related to the elastic constants, specific heat and melting point. Through the quasi harmonic Debye model, the dependency of Debye temperature on pressure P for various transition metal diborides is successfully obtained. The obtained results are consistent with the available theoretical results.