Abstract: A modified horizontal gradient-freeze approach with quasidouble parabolic temperature profile has been developed for growing GaAs single cryatals. Using this approach, the dislocation-free Si-doped crystals with <111>B and <211> B oriented seeds have been grown successfully. It has been found that the solid-liquid interface is slightly convex and nearly perpendicular to the growth direction during the growth process, indicating good thermal symmetry in the growth region, and so some deficiencies due to the inclined and slightly concave interface in conventional horizontal Bridgman growth could be avoided. Some other features in this approach are also discussed. It is suggested that the effectiveness of dopant Si for reducing the dislocation density of the crystals may be related to the interaction between Si_GaV_Ga complexes and dislocations.