A method for determining the distance from a while-drilling instrument to a stratigraphical boundary includes the steps that an actual measurement resistivity curve of a to-be-analyzed drilling well is acquired, the actual measurement resistivity curve of the to-be-analyzed drilling well is compared with a stratification true resistivity model, the stratum position of a stratum where a borehole ofthe to-be-analyzed drilling well is located is determined, and the stratum resistivity of the stratum position of the stratum and upper and lower surrounding rock of the stratum position of the stratum is determined; and according to the stratum resistivity of the upper and lower surrounding rock of the stratum position of the stratum where the borehole of the to-be-analyzed drilling well is located, a boundary metering signal corresponding to the borehole of the to-be-analyzed drilling well is determined, and through the boundary metering signal corresponding to the borehole of the to-be-analyzed drilling well, the distance from the while-drilling instrument of the to-be-analyzed drilling well to the stratigraphical boundary of the stratum position of the stratum where the borehole is located is determined. Due to the method, the advantages that a while-drilling electromagnetic wave resistivity instrument is large in investigation depth and rich in logging curve are fully played; andby means of the inversion and numerical simulation technologic means, under the condition that the logging items are not increased, stratum structural parameters can be obtained from an existing resistivity measuring curve.