The invention discloses a chromatographic overlapping peak treatment device. The device comprises a data collection module, a data analysis module, a baseline noise reduction module, a calibration fitting module and an overlapping peak treatment module. Wherein the data collection module is connected with the data analysis module, the data analysis module is connected with the baseline noise reduction module, the baseline noise reduction module is connected with the calibration fitting module, and the marking fitting module is connected with the overlapping peak treatment module. According tothe invention, the overlapped peak treatment module firstly determines a peak position by adopting a derivative method; overlapped peaks are determined through base point grouping, a simplex method isused for fitting a peak shape curve, so that information such as peak heights, peak widths and protrusions of all components of the overlapped peaks is determined, the peak position determining precision is high, the information precision of all the components of the overlapped peaks is high, peak division intervals can be automatically defined, and the number of sub-peaks in the overlapped peakscan be automatically determined.