A [4+2] annulation of two different styrenes to construct polysubstituted 1,2-dihydronaphthalenes was achieved. This transformation proceeded smoothly under electrochemical oxidative conditions without metal catalysts and external oxidants. A series of polysubstituted 1,2-dihydronaphthalenes were obtained with high regioselectivity and diastereoselectivity. Moreover, polysubstituded 1,2-dihydronaphthalenes were further transformed to polysubstituted 1,2,3,4-tetrahydronaphthalenes and polysubstituted naphthalenes, which showed great potentials in synthetic application.