The invention discloses a device for sensing temperature, which comprises a current source, a plurality of resistors, a binary counter, a multiplexer, a comparator and a control logic circuit, wherein the current source can supply absolute temperature ratio current; the resistors are connected in series between the current source and a ground terminal and generate m voltage signals which increaseor decrease orderly; the binary counter starts counting when receiving initial signals and generates n+1 bits of binary selection signals; the multiplexer is provided with m input terminals for receiving the m voltage signals, and outputs one voltage signal used as a multiplex output signal according to the binary selection signals, wherein m is greater than 2 but smaller than 2; the comparator receives multiplex output signals and reference voltage which does not change with the temperature, and generates comparative result signals; the control logic circuit outputs the initial signals, and ensures that the binary counter records the binary selection signals as binary temperature signals when the comparative result signals transfer potential.