The examination of plankton biodiversity through Permian-Triassic period seems to display different patterns of evolution depending of the scale of study (taxonomy stratigraphy or biogeography). In this paper we present the state of the art of the plankton turnover at the Permo-Triassic and we review more precisely the pattern of extinction and recovery of radiolarians during such period, because at that time, plankton was essentially represented by radiolarians. At a global scale the end-Permian to early Triassic period is marked by several strong extinctions in the marine realm, and in the radiolarians they occur progressively as exemplified by two orders of radiolarians: Albaillelaria and Latentifistularia. Nevertheless, this period is marked by a tremendous post-crisis diversification in both at family and generic level, more than extinction; an actualized revision of the diversity at the family level is also offered in our review. At a moderate scale (i.e. genera and in a region) the modifications appear impressive while at specific and regional domain the message is not so clear, one can wonder if some crisis manifestation results from a taxonomic accident or from preservative conditions. In fact, strangely enough more the number of studies is, more the diversity is high, and oppositely less they are, more the provincialism is evoked. RESUME L'examen de la biodiversité du plancton au passage Permien-Trias semble montrer différents types de manifestation selon l'échelle d'observation aussi bien en terme de stratigraphie que de taxonomie ou de géographie. A cette époque, le plancton était surtout représenté par les radiolaires. A une échelle globale cette période est certes marquée par des extinctions mais elles sont progressives comme le prouvent les deux ordres de radiolaires: les Albaillelaria et des Latentifistularia. Néanmoins cette période est surtout marquée par une énorme diversification post-crise, plus encore que par l'extinction. A une échelle moyenne (ex. niveau générique et celui d'un pays) les renouvellements de faune semblent impressionnants, alors qu'à l'échelle des espèces et de bassins particuliers, on est conduit à se demander si des modifications résultent de réelles crises biologiques ou de problèmes de conservation. Il est amusant de constater que plus le nombre d'études est élevé, plus la diversité apparaît grande et à l'opposé, plus elles sont rares, plus le provincialisme est évoqué. sic crisis within the sedimentary successions containing wellpreserved fossils indicate that during the Early Mesozoic a genuine radiation of microplankton took place, one that included heterotrophic as well as photoautotrophic protists. Undoubtedly, the radiolarians are the most important and dominant group among the microplankton after the Permo-Triassic crisis. This is the reason why we analyse in this paper the changes that occurred in this group.