In order to make clear the degenerative characteristics of gill external morphology in Ichthyophis bannanicus, 8 eggs at early stage of mature embryo were picked out randomly from the same clutch and the larvae were released from the capsule. Soon afterwards the left 9 eggs were monitored at late stage to observe the changes of gills before and after hatching. At early stage of mature embryo, initially embryonic gills (Fig. 1a) were red and inflated, filaments at almost right angle to gill axis; afterwards, the gill rami (Fig. 1b) were paled and the filaments turned curled and the angle between filament and gill axis smaller. At late stage of mature embryo and at the outset of newly born larvae, at the start the gill rami (Fig. 1c, d) were white, soft, filaments curled, angles smaller between filament and axis; subsequently, the gill ramus (Fig. 1e) striped off gradually. The result showed that the mode of the gills degeneration was not resorption, nor resorption with stripping, but only stripping, that obvious signs of external morphological changes can be seen during the degeneration process which includes 3 steps: less blood supply, halt of blood supply as well as death and stripping of gill rami and that at late stage of mature embryo, earlier hatching, more gill rami, otherwise, less rami will be kept and paled gill rami will fall off randomly.