A high-density and high-robustness sub-threshold memory cell circuit, having two PMOS transistors P1 and P2 and five NMOS transistors N1˜N5, wherein, the each base electrode of the two PMOS transistors and NMOS transistors N3, N4, and N5 is connected with the local grid electrode respectively; the base electrode of the NMOS transistors N1 and N2, are grounded respectively; the NMOS transistor N1 form an phase inverter with the PMOS transistor P1, and the NMOS transistor N2 form another phase inverter with the PMOS transistor P2; the two phase inverters are connected with each other in a cross coupling manner via the cut-off NMOS transistor N5, the output end of the phase inverter N1 and P1 directly connected to the input end of the phase inverter N2 and P2, and the output end of the phase inverter N2 and P2 connected to the input end of the phase inverter N1 and P1 via the cut-off NMOS transistor N5; the NMOS transistor N3 is connected with the write bit line (WBL) of the phase inverter N1 and P1, and the NMOS transistor N4 is connected with the NOT WBL and read word line (RWL) of the phase inverter N2 and P2.