As an earth-abundant and environmentally friendly material,SnSex(x = 1,2)was proved to have potential applications in solar cells,lithium ion batteries,photovoltaic devices and phase change memory,etc.However,the uniform nonmagnetic semiconducting properties greatly hinder their wider applications.1,2 Thus,the modulation of electronic and magnetic properties of SnSex is pressing needed.Recently,we have systematically studied the effect of strain on the electronic and magnetic properties of SnSex nanostructures by means of the first-principles DFT calculations.Our results showed that a semiconductor-metal or metal-semiconductor transition can always be triggered by applying different levels of strain,and surprisingly,magnetic behaviors can be induced in SnSe2 armchair nanoribbons.3,4 The density of state and partial charge density distribution were computed to explain these transitions and the binding energies were calculated to evaluate the possibility of experimental realizations.