BACKGROUND: The augmenter of liver regeneration (ALR) is a kind of important secondary liver regeneration factors, and it can particularity promote the liver regeneration. OBJECTIVE: To clone the RNA extracted from neonatal rat liver to ALR gene, and to analyze the gene using the bioinformatics. DESIGN, TIME AND SETTING: The study, gene molecule in vitro experiment, was performed at the Laboratory of Neurobiology, College of Life Science of Henan University between March 2008 and May 2008. MATERIALS: The liver tissues were harvested from 3-day-old Wistar rat of SPF grade. METHODS: Total RNA was exacted from rat liver tissues using guanidinium isothiocyanate-phenol-chloroform extraction method. According to the guideline of molecular biology experiment, the target fragment was amplified using reverse transcription-polymerase chain reaction. Alter purified, the target gene was recovered with gel recovery kit and subcloned to pGEM-T easy, and then was transformed to E.coli. The extracted piasmid was sequenced by Shanghai Sangon Biological Engineering Technology And Service Co., Ltd. The sequence was analyzed with molecular biological software. MAIN OUTCOME MEASURES: Polymerase chain reaction amplification band; analysis of gene sequence; sedne, threonine and tyrosine phosphorylation predictions; phytogenetic analysis of ALR. RESULTS: The potymerase chain reaction product was in concordance with target fragment. The analysis of the gene sequence proved it is the ALR gene. The overall length of the ALR gene was 378 bp, it was highly conservative in many species, for instance the Homo sapiens, the Mus musculus, the Bos Taurus and the Danio redo. CONCLUSION: In this experiment, we have cloned the ALR gene successfully.