A survey is given of the analysis of actinide nuclides by means ofa-spectrometry in high-level radioactivity process solutions resulting from reprocessing of spent U-Th fuel. Separation of fission products and isolation of the nuclides228Th,231Pa,232U,237Np and238Pu are performed by adsorption, ion-exchange, extraction chromatography and extraction techniques. After separation, samples for quantitative determination are prepared by electrodeposition and measured using a silicon-surface barrier detector combined with a multichannel analyzer. An error estimation is given.