The comprehensive investigation of protein phosphorylation and glycosylation aids in the discovery of novel biomarkers as well as the understanding of the pathophysiology of illness. In this work, a nitrogen/titanium-rich porous organic polymer was developed by copolymerizing carbohydrazide (CH) and 2,3-dihydroxyterephthalaldehyde (2,3-Dha) and modifying with Ti4+ (CH-Dha-Ti4+). The adequate nitrogen contributes to the enrichment of glycopeptides via HILIC, while titanium benefits from capturing phosphopeptides through IMAC. The proposed method exhibits excellent selectivity (1 : 1000, both for glycopeptides and phosphopeptides), LOD (for glycopeptides: 0.05 fmol μL-1, for phosphopeptides: 0.2 fmol), loading capacity (for glycopeptides: 100 mg g-1, for phosphopeptides: 125 mg g-1) and size-exclusion effect (1 : 10 000, both for glycopeptides and phosphopeptides). Furthermore, CH-Dha-Ti4+ was applied to capture glycopeptides and phosphopeptides from human serum; 205 glycopeptides and 45 phosphopeptides were detected in the serum of normal controls; and 294 glycopeptides and 63 phosphopeptides were found in the serum of uremia patients after being analyzed by nano LC-MS/MS. The discovered glycopeptides and phosphopeptides were involved in several molecular biological processes and activities, according to a gene ontology study.