Abstract: A novel method using QconCAT protein combined with <sup<18</sup<O-labeling technique and multiple reaction monitoring mass spectrometry was established to quantify proteins involved in the pathway of adipose synthesis and β-oxidation.Firstly,the QconCAT proteins were constructed,and expressed in <i<Escherichia coli</i<.The digestion and the <sup<18</sup<O labeling efficiency were optimized.Secondly,the novel method of quantifying adipose synthesis and β-oxidation was developed.Lastly,target proteins of obesity and control groups were quantified by MRM.The results showed that the abundance of the enoyl ACP reductase and malonyl-COA ACP transferase increased significantly in the obesity group with <i<P</i<<0.05.It is consistent to previous reports and means the method had its reliability to analyze the biological sample.