Magnolol and honokiol, the main components of Magnoliae Cortex, were isolated and used as the standard substances for the analysis. In order to determine the contents of magnolol and honokiol in Magnoliae Cortex originated from Korea, China and Japan, both HPLC and HPTLC methods are applied and compared with each other. The components were separated on C8 column with acetonitrile-water-acetic acid (50:50:1) in HPLC and detected at UV 294nm. The components separated on HPTLC precoated silica gel plate with chloroform-methanol (9:1) were detected directly on the plate at 254nm. The contents of magnolol and honokiol in Magnoliae Cortex were in the wide range of 0.01~2.8% and 0.005~0.8%, respectively, according to their purchase places. It is also applicable to the quality control of various preparation from Magnoliae Cortex.