Based on the transcriptome of Larix kaempferi, a 1,590 bp APETALA2-Like gene containing initiation and terminator code was obtained by RT-PCR and named LaAP2L1. This cDNA encodes a predicted protein containing 529 amino acids, which form a 58.327 kD polypeptide with a calculated pI of 6.45. The secondary structure of LaAP2L1 contained alpha helixes, extended strands and loops. Alignment of predicted amino acid sequences of LaAP2L1 in different plant species showed this transcription factor was highly homologous with the reported APETALA2-like in Pinus thunbergii and Picea abies. To elucidate the function of LaAP2L1, LaAP2L1 overexpression vector driven by an enhanced CaMV 35S promoter was constructed and transformed to Arabidopsis via dip flower. Compared with the empty vector control lines, the LaAP2L1 overexpressed transgenic plants had remarkably enlarged leaves, stems, flowers, and plant height, suggesting an important molecular role of LaAP2L1 in regulating plant organ development.