In this study, an efficient screening program was established with ARTP. Five strains from oleaginous microalgae Chlorella pyrenoidosa were screened from mutant library after mutagenizing by ARTP. Among them, the optimal mutant strain was named as II-H6. In the BG11 medium, the OD680 of II-H6 in stationary phase were increased by 32.08% than the original strain. Meanwhile, compared with the original strain, the dry weight and lipid productivity of II-H6 were increased by 22.07% and 16.85%, respectively. II-H6 showed a good genetic stability in BG11 medium and the optimum growth temperature and pH were 33 degrees C and 9.0. 18S gene fragment length of II-H6 strain were 1886 bp. Analysis of the gene fragment showed that the II-H6 strain had a close relationship to the original strain, and it belonged to the mutation within the genus Chlorella. (C) 2017 Elsevier Ltd. All rights reserved.