Abstract: Reported herein are eight solid complex compounds obtained by reactions of uranyl nitrate, uranyl chloride and thorium nitrate with macro-cyclic polyethers dibenzo-18-crown-6, benzo-15-crown-5 and 18-crown-6 in polar solvents. The complex compounds have been characterized by elemental analysis, melting points and infrared spectro-metric analysis.The experimental results indicate that among the mentioned eight compounds four are different in composition-from those reported in literature. Their molecular formulas are: UO2(NO3)2.2H2O-DB18CR62; Th(NO3)43DB18CR65 3H2O;. Th(NO3)42 B15CR53 2H2O; Th(NO3)42 18CR63.2H2O. The melting points of the complex compounds are higher than the corresponding crown ethers, with the exception of UO2(NO3)22H2O DB 18CR62 with a melting point of 148-150℃, while the m.p. of its corresponding crown ether DB18CR6 is 161-163℃. The three uranyl nitrate crown ether complex compounds all have melting points of about 150℃. The vibrational frequences in IR spectra of the complex compounds can be regaraded as characteristic of the synthesized complex compounds.