To clarify the effects of Ultraviolet-B (UV-B, 280-315 nm) treatment on the energy transfer process in photosynthesis, steady-state absorption and fluorescence techniques are performed on thylakoid membrane and photosystem II (PSII).The results show that under greenhouse, lower UV-B radiation levels do not inhibit light energy transfer process. Plant ensures energy reach to reaction center through a series of adjustment mechanism. These mechanisms include enhancement of absorb intensity of short-wavelength-absorption pigments, regulation of energy distribution between two photosystems and the changs of conformation and (or) location about pigment-protein system.