The effects of filtering with different filters on analytical results and precisions of MOMEO elements have been studied in this paper. In view of the authenticity of the measured results of MOMEO elements and the properties of soil colloid, the 2 μm pore diameter membrane is determined as the optimal filter employed in MOMEO survey. It is of great significance to the normalization of MOMEO survey method. The application test shows that the 2 μm pore diameter membrane can be effectively used in MOMEO survey.