Large-scale identification of N-linked glycopeptides by liquid chromatography coupled tandem mass spectrometry (LC-MS/MS) in human serum is challenging due to the wide dynamic range of serum protein abundances, the lack of a complete serum N-Glycan database, and the existence of non-specifically digested peptides and numerous modifications. In this regard, we present a spectral-library search method for serum N-linked glycopeptide identification with target-decoy and motif-specific false discovery rate (FDR) control. Low-abundant glycoproteins were firstly separated from high-abundant proteins by acetonitrile precipitation. After digestion, the N-linked glycopeptides were enriched by hydrophilic interaction liquid chromatography (HILIC) column and processed by Glycopeptidase F (PNGase F) to generate de-glycopeptides, the spectra of which were utilized for library construction. From the de-glycopeptide datasets, 618 glycoproteins with 1,302 N-linked glycosites and 3,000 unique de-glycopeptides were identified. Four types of N-glycosylation motifs were used to recognize the de-glycopeptides, and two different N-Glycan mass databases including 27 modified N-Glycan masses and 712 unmodified N-Glycan masses were utilized during library search. In total, 439 glycoproteins, 851 occupied N-linked glycosites, 24,317 unique glycopeptides and 738 N-Glycan masses were identified under 1% FDR, representing the most in-depth serum N-glycoproteome identified by LC-MS/MS method at glycopeptide level.