Effect of electron irradiation on supercooled liquid in Zr_66.7Cu_33.3, Zr₆₅Al_7.5Cu_27.5 and Zr₆₀Al₁₅Ni₂₅ metallic glasses was investigated by in situ TEM observation. The electron irradiation induced crystallization occurred in the supercooled liquid with nucleation and growth mode similar to that by thermal annealing. The electron irradiation accelerated crystallization resulting in different size and morphology of precipitates from those by thermal annealing. There was no significant difference in phase selection and crystallization mode of supercooled liquid between thermal annealing and electron irradiation, while electron irradiation induced crystallization behavior of an amorphous phase was different from that of thermal crystallization.