A visible-light-induced cascade arylazidation of activated alkenes with trimethylsilyl azide (TMSN3) has been developed. Mechanistic investigations reveal that the single electron transfer (SET) of TMSN3 with the excited photocatalyst was involved in the initial step, followed by radical addition/aryl migration/desulfonylation to furnish valuable α-aryl-β-azido amides and azidated oxindoles under mild conditions, which are versatile building blocks in organic synthesis. With simple treatment, the obtained arylazidated products were further converted to valuable β-amino amide and 1,2,3-triazole derivatives.