A method of reversed-phase high performance liquid chromatography (HPLC) coupled with evaporative light scattering detection (ELSD) was developed for the determination of α-solanine and α-chaconine in potato，and determine the contents in different samples. The results showed α- solanine and α- chaconine can be obtained good separation and high efficiency peaks when took 0.1% trifluoroacetic acid water and acetonitrile as mobile phase with gradient elution, and the drift tube of ELSD detector was 98 ℃, the pressure of nebulizing gas was 6.90 kPa. α-solanine and α-chaconine could be extracted with 100 times the mass 1% formic acid in methanol at 70 ℃ with 90 min, the extract liquid was injected into the chromatograph for testing directly. The linear calibration curve of α- solanine was obtained in the ranges of 0.196～9.800 μg (R²=0.999 5), the average recovery was 99.4%, the contents of α- solanine and α-chaconine be calculated with α- solanine standard curve simultaneously; There were different alkaloids contains in different parts of the potato plant, α-solanine contents were 0.13～1.59 mg/g and α-chaconine contents were 0.39～8.28 mg/g; total alkaloids were 0.52～9.37 mg/g, α-chaconine contents were 1.2 to 7.6 times of α- solanine contents in the same sample。