Ti-pillared　montmorillonites　have　been　prepared　by　hydrolysis　and　Sol-Gel　methods.　Fourier　infrared　spectroscopy　of　pyridine　adsorption　has　been　used　to　determine　acid　sites　on　Ti-PLMs.　Hydroxy　and　Bronsted　acid　sites　on　the　montmorillonites　have　been　identified.　There　are　both　Bronsted　and　Lewis　acid　sites　on　the　Ti-PLMs.　The　Ti-PLMs　prepared　by　hydrolysis　have　more　L　and　less　B　acid　sites　than　Ti-PLMs　prepared　by　Sol-Gel.　It　is　proposed　that　the　acid　sites,　especially　B　acid　sites,　on　the　Ti-PLMs　originate　from　the　pillars　in　Ti-PLMs.