［Objective］Inorganic potassium silicate coatings had comprehensive advantages suchas ultra-low volatile organic compound（VOC）emissions，low cost，weather resistance，flame retardancyand breathability. However，the poor water resistance limits their application.［Methods］High SiO₂/K₂O ratio potassium silicate that feature storage ability was firstly prepared by compounding low SiO₂/K₂O ratio potassium silicate with silica sol，further modified by potassium methylsilicate（PMS） and methyl trimethoxysilane to enhance its water resistance. Finally，the waterborne inorganic potassium silicate coating was obtained by carefully mixing styrene acrylic latex，fillers and other additives，and the adhesion，hardness，water resistance，and other properties of the coatings were characterized.［Results］The results showed that the potassium silicate with 5. 4 SiO₂/K₂O ratio had storage stability，and the PMS-modified samples exhibited significantly enhanced resistance to alkaline water. When the PMS content was 5% and the emulsion content was 6%，the prepared coating exhibited optimal performance，achieving Class 1 adhesion，H pencil hardness，a surface drying time of 6 minutes，and no abnormalities after 168 hours of alkaline resistance testing.［Conclusion］ This coating had good water resistance and basically met the requirements of T/CSTM 00632. 3—2022 Technical Requirement for Coatings Used in Architectural Finishing Engineering-Part 3：Inorganic Architectural Coatings System，featuring application prospects in interior wall coatings.