Microalgae is becoming a promising candidate for biofuel production and energetic lipid production, which urges the need to develop efficient methods for improvement of the lipid production. In this study, the neutron irradiation was employed to improve lipid production under different dosage irradiation. Effects of different dosages (No.1: 8.14 x 10(9), No.2: 5.64 x 10(8), No.4: 9.42 x 10(7) n/cm(2)) were compared by investigating associated algae cell growth, total lipid production, metabolization and enzyme activity. Dosages No.2 and No.4 improved the lipid content without negative influence on the growing, whereas irradiations shortened the period of biomass accumulation. The neutron irradiation in No.2 accelerated the synthesis of lipid from the carbohydrate transition process. In addition, the neutron irradiation not only increased the total lipid production by 20% but also speeded up the reaction rate to reach the maximal total lipid production in 28 days. Our results can provide a better understanding of the lipid production in microalgae Chlorella sp. by neutron irradiation, which are critical for evaluation of neutron irradiation based technologies for the sustainable and renewable biofuel production. (C) 2016 Elsevier Ltd. All rights reserved.