Polycrystalline Tb x (Pr 0.5 Nd 0.5 ) 1−x Fe 1.93 (0.0⩽x⩽0.4) cubic Laves alloys were synthesized by arc-melting and subsequent high-pressure annealing. The structure, magnetic properties and magnetostriction of the alloys were investigated. These alloys exhibit single cubic Laves phase with MgCu 2 -type structure due to the effects of high-pressure annealing. The absolute value of the first anisotropy constant |K1| decreases with increasing Tb content to a minimum at x=0.1 and then increases with further increase in x. The magnetostriction λa=λ‖-λ⊥ of the sample with x=0.1 is much larger and easier to get saturation than the others. In addition, the large ratio between magnetostriction and the absolute values of the first anisotropy constant λa/|K1| appears at the sample with x=0.1, which may make it a potential material for magnetostrictive application.