To address the limitations of traditional planar two-dimensional displacement sensors in ultra-precision lithography and large-area sensor manufacturing, a new method using a spatial alternating magnetic field is proposed. This method involves arranging uniform sine/cosine excitation windings on a fixed ruler and applying time-quadrature electric current to these windings, creating a two-dimensional alternating magnetic field that links spatial displacement with a time reference. The method achieves spatial displacement measurement through a model of "dimension judgment + displacement decoupling." Dimension judgment is performed using the binary output signals from a dimension-judgment induction winding array. The alternating magnetic field is detected by a displacement-decoupling induction winding array arranged in two dimensions, producing spatial traveling-wave signals and enabling displacement decoupling via phase comparison. Error analysis of this two-dimensional time-grating displacement measurement model was conducted through electromagnetic simulation. A prototype and experimental platform were developed, demonstrating that within a 120 mm × 120 mm range, the maximum measurement errors were ±9.4 µm in the X direction and ±9.7 µm in the Y direction, with a resolution of 0.15 µm. This method achieves micron-level measurement accuracy using millimeter-sized excitation and induction windings, overcoming the limitations of traditional sensors in ultra-precision lithography and simplifying sensor manufacturing. The research holds significant theoretical and practical value.