Ab initio calculations of optical-phonon deformation potentials (ODP)d30, d10 (val) and d10 (cond) on Λ-axis in Brillioun zone for the compounds GaAs and AlAs are reported. The study is based on a frozenphonon model and using the LMTO-ASA method with a frozen-potential approximation, in which the displacement of the empty sphere was considered +o match its atomic sphere partners. The validity of our method and results have been verified with the aid of calculations for wave-vector dependence of the ODPs on Λ-asix, the numerical test to the expressions about d0 VS d30 and d10 VS d10 (val) near Γ point and an extensive comprison with various calculations as well as the experiment.