A process corner detection circuit based on a self-timing ring oscillator comprises a reset circuit (1), the self-timing oscillation ring (2), and a counting module (3). The self-timing ring oscillator (2) consists of m two-input Muller C-elements and inverters, and a two-input AND gate, m being a positive integer greater than or equal to 3. The circuit can be used for detecting a process corner of a fabricated integrated circuit chip, and reflecting the process corner of the chip according to the number of oscillations of the self-timing ring oscillator (2). The number of oscillations of the self-timing ring oscillator (2) in different process corners is acquired by Hspice simulation before the chip tape-out, and the process corner of the chip after the chip tape-out can be determined according to the actually measured number of oscillations.