This paper investigates the influence of the short-channel effects（SCEs）on the static noise margin（SNM）of 6T（6 transistors）SRAM composed of 2D MOSFETs.An analytical all-region I-V model for short-channel complementary 2D MOSFETs has been developed,and a simulation model has been built to calculate SNM with the consideration of SCEs and velocity saturation.The results show that there exists an optimal value of channel length(L_opt)where SNM reaches a maximum,and L_opt is approximately three times the scale length.In the region where L>L_opt,SNM increases slightly as L decreases because of velocity saturation,while in the region where L<L_opt,SNM decreases rapidly as L decreases as the SCEs are dominant.The worst case of SNM reduction due to the threshold voltage（V_T）fluctuation is investigated,and the maximum V_T tolerance is studied as a function of L.In an SRAM with a scale length of 5 nm,as L decreases from 15 nm to 5 nm,SNM decreases from 155 mV to 98 mV,and the maximum V_T tolerance decreases from 126 mV to 105 mV.