Phosphorylated　peptides　are　crucial　for　understanding　biological　regulation　processes.　However,　the　detection　of　phosphorylated　peptides　remains　challenging　in　mass　spectrometry　(MS)　due　to　their　high　hydration,　low　abundance,　and　the　significant　signal　suppression　caused　by　non-phosphorylated　peptides.　It　is　essential　to　enhance　the　efficiency　of　phosphopeptide　enrichment　from　complex　biological　samples　to　achieve　comprehensive　analysis　and　identification　of　phosphopeptides.　Herein,　a　packed　in-tube　solid-phase　microextraction　(IT-SPME)　method　was　developed　based　on　mesoporous　zirconium　titanium　oxides　for　the　selective　enrichment　and　analysis　of　phosphopeptides.　The　IT-SPME　system　achieved　the　efficient　capture　of　phosphopeptides　from　complex　biological　samples　followed　by　high-sensitivity　detection　(5　fmol).　This　exceptional　performance　can　be　attributed　to　the　high　surface　area　(289.77　m2/g)　of　mesoporous　zirconium　titanium　oxides,　which　provided　abundant　active　sites　for　a　high　loading　capacity.　The　zirconium　titanium　oxides　with　a　mesoporous　structure　(∼4.5　nm)　was　prepared　through　a　sol–gel　and　solvothermal　process.　Importantly,　this　method　proved　effective　in　enriching　phosphopeptides　from　practical　samples　such　as　non-fat　milk　and　egg　white.　It　is　the　first　attempt　to　employ　a　mesoporous　packed　IT-SPME　approach　for　phosphopeptide　enrichment.　These　results　demonstrate　the　significant　application　potential　of　mesoporous　zirconium　titanium　oxides　in　phosphoproteomics.　©　2023　Elsevier　B.V.