Abstract: Microalgae is an ideal biological resource to produce biodiesel. It is important to study the physiological and biochemical characteristics of lipidrich microalgae. In this study, Palmellococcus miniatus, a kind of alkaliresistant green microalgae, was cultured under low (100 μmol photons·m^-2·s^-1) and high (600 μmol photons·m^-2·s^-1) light, and the effects of nitrogen deficiency on photophysiology and lipid accumulation of P. miniatus were investigated. The results showed that nitrogen deficiency decreased the photosystem II maximum photochemical yield (F_v/F_m), inhibited the electron transfer from Q_A^- to Q_B, and lowered the protein content. The inhibition of photosynthesis resulted in the reduction of the growth and biomass. However, nitrogen deficiency induced significant accumulation of lipid. When supplemented with high light, the photosynthesis of P. miniatus was further suppressed and the protein content was decreased to a great extent. In contrast, the lipid content did not show significant change as compared with that under the low light and nitrogendeficient condition. Our results indicated that lipid accumulation was stimulated by nitrogen deficiency, while light intensity showed little effect on it.