The invention relates to current equipoise circuit which is used in the folded interpolation structure analog to digital converter, it belongs to technology field of electronic equipment. It includes: two first PMOSes form the first current mirror, the source end is connected with the positive output of the folded circuit, the output end is coupled with the positive output and then output; two second PMOSes form the second current mirror, the source end is connected with the negative end of the folded circuit, the output end is connected with the input end of the third current mirror; two NMOSes form the third current mirror, the source end is connected with the output end of the second current mirror, the output end is coupled with the negative end of the folded circuit, and then added with the coupled signal as the output of the equipoise circuit. The invention of equipoise circuit, it can restrain the common-mode plus output by the folded circuit of analog-to-digital converter effectively, increase the puckering curve range output by the folded circuit, equipoise the zero-crossing point of the folded curve, decrease the requirement of sensitivity of back-end comparator.