Abstract: In this paper,the effect of transverse are oscillation under magnetic control (TAOMC) on solidification cracking in TIG welds of LD10CS and LY12CZ Al-alloys was investigated by modified fishbone crack test.It was found that with appropriate choice of frequency and amplitude of are oscillation,the solidification cracking of LD10CS Al-alloy can be dramatically reduced,and the solidification cracking of LY12CZ Al-alloy can also be reduced to a certain extent.Based on the metallographic examination of the macrostructure and microstructure of weld metal,a new mechanism for reducing weld solidification cracking was proposed and studied.