A new kind of magnetic grid absolute linear displacement sensor is introduced. The displacement measuring method of two new kinds of magnetic grid sensors for single-row and double-row magnet are also proposed in this paper. The double-row magnet sensor is composed of the look-up table column and encoding column, the look-up table column achieves the calculation of relative displacement within a cycle. Precision of the double-row magnet sensor is analyzed and the resolution can reach 0.75µm. The displacement measurement of single-row magnet is realized by adding Hall group based on the encoding column. The signal is processed according to the voltage curves induced by multi-group of Halls.