In the present paper,the research on the parameter determination of Chaboche thermal viscoplastic constitutive model has been carried out and a method is proposed.By using this method a set of parameters for the material TiAl has been determined.Furthermore the finite element analyses by using the UMAT coded by Arzt and Brocks et al associated with above parameters for uniaxial tension at different rates, uniaxial creep under different stress levels and creep procedure of a CT specimen under a ladder type load have been performed.