In this paper, we report a new method based on solid phase extraction (SPE)–gas chromatography–high resolution Orbitrap mass spectrometry for the migration detection of 16 nitrosamines and their nitrosatable substances from children’s products. The method exhibited high mass accuracy for targeted ions of all substances, providing a solid foundation for the elimination of matrix interference, and showed high accuracy and sensitivity in the detection of trace nitrosamines. The SPE regularity of nitrosamines was explored on the basis of the results of orthogonal experiment and variance analysis. Through quantitative characterization and visual comparison, the significant order of influencing factors of SPE and the interaction between factors were determined. The optimal extraction conditions were obtained by using HR-P cartridge, 350 mg, and ethyl acetate. The limit of quantification ranged from 0.03 µg/kg to 0.38 µg/kg. A linear range of 0.03 µg/kg to 60 µg/kg was also observed with r2 ≥ 0.9945. Spiked at different levels (LOQ, 1.25 and 12.5 µg/kg), the recoveries ranged from 85.7% to 101.5%, and the relative standard deviations varied from 2.2% to 9.9%. Finally, 45 children’s products were screened to inspect nitrosamine levels. Results indicated that N-nitrosodimethylamine, N-nitroso-N-methylaniline, and N-nitrosodibenzylamine were detected (3.1–307.5 µg/kg), posing a potential hazard to children’s safety.