OBJECTIVE To develop a high performance liquid chromatographic method utilizing high speed scanning technology for the determination of cyclosporin A (CsA) in human whole blood. METHODS Adding HCl 2 ml of HCl solution( 0.025 mol·L -1 ) to whole blood sample, mixed the mixture well and extracted with 3 ml of ether twice. Ether layer was washed with 2 ml of NaOH solution( 0.025 mol·L -1 ) and evaporated to dryness after isolation. The residue was dissolved in 60 μl of acetonitrile water(70∶30) solution and 20 μl was injected for the determination after washed by 800 μl of n hexane. Elution was performed on Elite C 18 column(220 mm× 4.6 mm ) with methanol water(88∶12) as mobile phase. The flow rate was 1.0 ml·min -1 and column temperature was maintained at 65℃. The scanning wavelengths were from 205 nm to 250 nm with a 5 nm interval and 210 nm was elected as the integration wavelength.RESULTS A linear relationship was obtained between the peak areas and CsA blood concentration from 50 ng·ml -1 to 1000 ng·ml -1 ( γ = 0.9989 ). The extraction recoveries of CsA from whole blood were 92.03% ～ 93.13% . RSD within day and between days were less than 5.3% ( n =5) and 6.1% ( n =5) respectively. Spectra analysis function of spectra FOCUS Software could be used to analyze the peak purity. CONCLUSIONS The method is accurate,stable and simple. The analyst could find if the peak of CsA is interfered by other concomitant drugs, so the method is very suitable for routine clinical monitoring of CsA concentration.