[en] The corrosion products on the I-SCC fracture of Zr-Sn-Nb alloys have been investigated by SEM and EDXA. The result shows that, the products are mainly composed of Zr and O; and I can only be detected on the local pseud-cleavage zone. The adsorption of iodine at bare metal surface would be competing with that of oxygen. This could lead to the formation of a non-protective film and thus promote locally serious oxidation in test atmosphere. The stress, iodine partial pressure, composition of alloys and heat-treatment state would influence the morphology and thickness of the corrosion products, which can be explained by the diffusion of iodine, the quantities of precipitation particles or the reaction balance of Zr-I-O system