The diacylglycerol acyltransferase gene PaDGAT1 (The accession number in GenBank: MG214258) was cloned from seed of Paeonia suffruticosa by the method of RTPCR and RACE. The fulllength cDNA of PaDGAT1 gene was 2 028 bp, with an open reading frame of 1 554 bp encoding 517 amino acids. The PaDGAT1 gene encoding protein was a hydrophobic alkaline protein with molecular weight of 58.86 kD and the academic isoelectric point of 8.62. Prediction of secondary structure showed that the random coil and extended strand were the main structural elements of the protein. Amino acids sequences alignment analyses indicated that the amino acid sequence of PaDGAT1 belongs to DGAT1 subfamily, which was closed to DGAT1 from Olea europaea. The qRTPCR analyses showed that the expression level of the PaDGAT1 gene was the highest in bud, and was lower in leaf, stem and undeveloped ovary. During the seed developing, the expression level of PaDGAT1 gene in developing seed showed a trend of increasing firstly, then decreasing and increasing again. The expression level of the PaDGAT1 gene was the highest at 28 d in developing seed, then the level was decreased gradually, and was increased again at 70 d with a higher level at 85 d in developing seed. After harvest, the expression of the PaDGAT1 gene was increased with the highest level in seed under room temperature after harvest for 7 d, then it was decreased gradually. The results implied that the PaDGAT1 gene play an important role in the lipid synthesis during seed developing and maturing.