Аннотация:We analyze IUE-spectra of the symbiotic Nova PU Vul obtained in 1991-1996 (nebular phase). We show that in 1991-1996 the spectral energy distribution of the PU Vul can be explained with the standard model, which consists of hot component's radiation and nebular radiation unlike previous ``supergiant phase'' (1978-1987). The temperature of the hot component increased from 74000 K (1991) to 100000 K (1996) and the hot component's track on the H-R diagram matched to the theoretical track for a degenerate dwarf during hydrogen shell flash. On the base of the UV-observations of the eclipse in 1993-1994 we estimate the cool component's radius R_{cool}≥ 285 R_{⊙}. Asymmetry of the Rayleigh scattering of the hot component's radiation on the neutral hydrogen in the cool component's atmosphere make it possible to suppose that the mass loss rate of the cool component of PU Vul is variable