The electric field-assisted (EFA) heat treatment is proposed to solve the problem of excessive grain growth of β phase duringthe heat treatment of ZrTiAlV alloy. The effect of the EFA heat treatment process on the phase transformation and microstructureof the as-forged and severe plastic deformation (SPD) alloys are studied. For the as-forged 47Zr alloy, the pure βphase can be obtained by holding at 700 °C for 5 min. After SPD, the increase in defect concentration in the alloy reducesthe effectiveness of the EFA heat treatment, and required an extension of the holding time to 15 min to obtain a pure β phase. Furthermore, a new mechanism for the transition of needle-like α phase to β phase is proposed. Dislocations in the β-phasematrix shear the needle-like α phase, resulting in the formation of a large number of stacking faults inside it, which are thentransformed into the β phase through atomic plane slippage.