Abstract: The separation of the HPLC-DAD data set is an important issue in the field of chemometrics and is also the foundation of many other researches. By means of the reference curve model, this paper constructs a kind of 3-parameter reference curve for chromatogram peak and proposes an optimization algorithm of parallel nonlinear least square to solve the reference curve model. It is shown via simulations and experiments that compared with other methods, the proposed method has higher resolution, quicker convergence and easy control of parameters.