A homemade LC-MS interface was developed.The interface included atmospheric interface,ion source and electronic communication interface which connected to high-performance liquid chromatography and mass spectrometry′s software.The team self-developed API-TOFMS 10000 was successfully linked to Thermo Fisher Scientific Diana U3000.Experimental results showed that the self-built LC-MS was operated with a good stability(RSD=5.6%),the linear correlation coefficient(r2) was 0.995 8,the detection range: 2-2 000 pg,the limit of quantitation: 2 pg,and the detection limit: 0.5 pg.Piroxicam,theophylline and prednisone could be obviously detected.The experimental data showed that the self-developed LC-MS interface could meet the testing requirements,and the self-built LC-MS has an application potential in biochemistry,pharmaceutical analysis,food safety,environmental detection etc.