A haloalkaliphilic strain (IM 1326^T) was isolated from brine sampled at a soda lake in the Inner Mongolia Autonomous Region, China. Cells of the strain were rod-shaped and motile. Strain IM 1326^T was able to grow at 4–42 °C (optimum, 37 °C) with 0–13.0 % (w/v) NaCl concentrations (optimum at 4.0–6.0 %) and at pH 7.5–11.0 (optimum at 9.0–10.0). The 16S rRNA gene phylogenetic analysis revealed that the isolate belongs to the genus Aliidiomarina and is closely related to the type strains of Aliidiomarina sanyensis (95.8 % sequence similarity), Aliidiomarina shirensis (95.7 %), Aliidiomarina iranensis (95.4 %) and Aliidiomarina haloalkalitolerans (95.3 %). The whole genome of strain IM 1326^T was sequenced, and the genomic DNA G+C content was 49.7 mol%. Average nucleotide identity, average amino acid identity and digital DNA–DNA hybridization values between the isolate and the related Aliidiomarina species were 68.1–84.9 %, 76–78 % and 18.4–20.4 %, respectively. The respiratory quinone was ubiquinone-8. The polar lipid profile included diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and one unidentified aminophospholipid. The predominant cellular fatty acids were summed feature 9 (10-methyl-C_{16 : 0}/iso-C_{17 : 1} ω9c, 22.2 %), iso-C_{15 : 0} (16.1 %) and iso-C_{17 : 0} (13.1 %). Based on the results of phylogenetic analysis, genome relatedness, and the physiological and chemotaxonomic properties of the isolate, strain IM 1326^T is considered to represent a novel species of the genus Aliidiomarina , for which the name Aliidiomarina halalkaliphila sp. nov. is proposed (type strain IM 1326^T=CGMCC 1.17056^T=JCM 34227^T).