The invention provides a two-step incremental analog-digital converter. The two-step incremental analog-digital converter comprises a trigonometric integral modulator and a decimation filter, wherein the trigonometric integral modulator is composed of an adding circuit, N-1 cascade integrators, stepped selection integrators, a comparator, re-selectors and a digital-analog converter; the decimation filter is composed of an N-order digital filter and an decimator; one input end of the first re-selector is connected to an input signal Vin; the output end of the first re-selector is connected to the adding circuit; the output end of the adding circuit is connected to the N-1 cascade integrators; the output ends of the N-1 cascade integrators are connected to the input end of the second re-selector; the output end of the second re-selector is respectively connected with the first stepped selection integrator and the second stepped selection integrator; the output ends of the first stepped selection integrator and the second stepped selection integrator are connected to the input end of the third re-selector; simultaneously, the output end of the first stepped selection integrator is connected to another input end of the first re-selector; the output end of the third re-selector is connected to the comparator; and the output end of the comparator is respectively connected with the adding circuit and the decimation filter. The two-step incremental analog-digital converter disclosed by the invention is high in precision, low in power consumption, rapid to convert and high in signal-to-noise ratio.