Chemical cross-linking mass spectrometry (XL-MS) is a powerful research tool for exploring protein-protein interactions and their three-dimensional structures. To further increase cross-link coverage, a novel, methyurazole-derived, enrichable trifunctional cross-linker—phospho bismethylurazole (pBMT) was developed. The phosphate group, a small affinity tag, successfully separates cross-linked peptides from high-abundance noncross-linked peptides. The cross-linking strategy was developed to target multiple amino acid types ( i.e., tyrosine and histidine) under electrochemical and photochemical conditions without additional side reactions. This method was applied to cross-linking peptides, proteins, protein complexes, and cell lysates. Analysis of cross-linking results indicates that the pBMT-based cross-linking strategy provides abundant and accurate information for facilitating protein structure elucidation. Altogether, pBMT provides a novel chemical biology tool and innovative thought for the in-depth exploration of dynamic interactions between proteins