Abstract: Plant endogenous cytokinins(CTK) and auxin(IAA) usually function at the same time,and thus a method that can detect these plant hormones simultaneously is of great importance in studying plant physiological processes.The contents of 6 endogenous CTK components and IAA in plant tissues could be determined simultaneously by HPLC.Re-sults showed that with reversed-phase column HibarRT250-4.6,at constant temperature of 45℃,and with methanol-1% acetic acid(40∶60,v/v) as mobile phase,the components could be precisely separated and determined at a flow rate of 0.6 mL/min by isocratic elution and with a UV detector at 269 nm.The detectable limitation of this method was as low as 0.001 mg/L.Steps of the extraction and purification of samples were also improved to avoid the disturbance of the impurity and pigment on the sample.These suggested steps provided an effective way to study plant hormones responding to environments.