OBJECTIVE To establish a method for simultaneous determination of the contents of muilti-constituents in tall gastrodia capsules for quality control. METHODS The HPLC was performed on a Phenomenex Hydro-RP 80A (4.6 mm×150 mm， 4 μm) column with a mixture of methanol-0.1% H₃PO₄ solution as the mobile phase in a linear gradient elution mode. The flow rate was 1 mL·min^-1， and the column temperature was set at 40 ℃. The detection wave length was set at 270 nm. RESULTS The linear ranges were 0.40-6.4 μg (r=0.999 7) for gastrodin ， 0.064-1.0 μg(r =0.999 8) for 4-hydroxybenzyl alcohol， 0.020-0.32μg(r =0.999 7) for 4-hydroxybenzaldehyde ， 0.60-9.5 μg (r=0.999 9) for parishin， respectively. The average recovery were 100.8%（RSD 2.3%）、100.5%（RSD 3.4%）、101.9%（RSD 2.1%）、100.4%（RSD 2.5%）， respectively. Six constituents were determined. The average content of the 6 constituents of 25 samples were 2.189%（RSD 3.40%）. CONCLUSION The method is reliable and can be used for the quality evaluation of tall gastrodia capsules.