The present invention discloses a MEMS chip including a substrate with a back cavity; a capacitance system disposed on the substrate including a back plate, a membrane opposite to the back plate forming an inner cavity; a protruding portion accommodated in the inner cavity, fixed on one of the back plate and the membrane and spaced apart from the other along a vibration direction; a reinforce portion fixed to the membrane, having an area smaller than that of the membrane; a support system configured to support the capacitance system, including a first fixation portion suspending the membrane on the substrate, and a second fixation portion suspending the back plate on the substrate. The MEMS chip has higher sensitivity, higher resonance frequency and higher low frequency property.