This paper has developed the simultaneous determination method of n-Dodecane, Phenanthrene and Phenol in water sample by gas chromatography-mass spectrometry, and studied the distribution mechanism and its affecting factors in the coexistence system of n-Dodecane, Phenanthrene and Phenol of petroleum hydrocarbon contaminants in soil-water system of south China. The results show that the adsorption of the three contaminants in soil can be well described by the second-order kinetic equation, with the adsorption rate of n-Dodecane > Phenanthrene> Phenol. In the experimental concentration range, the adsorption isotherms of n-Dodecane and Phenol can be well fitted by Freundlish isotherm equation, while the Langmuir isotherm equation can be employed for the fitting of the adsorption isotherms of Phenanthrene. Moreover, the adsorption of n-dodecane and phenanthrene in the soil is a spontaneous exothermic process, whereas the adsorption of phenol is a spontaneous endothermic process, and the adsorption of soil to the three contaminants is dominated by chemical adsorption. The sorption efficiencies of n-dodecane and phenanthrene are in positive correlation with the organic matter content in the soil, and the correlation coefficients are 0.94 and 0.85, respectively. The order of n-dodecane adsorbed by soils in different particle size is: silt> clay > fine sand > coarse sand, the order of phenanthrene adsorption is: silt＞fine sand >clay> coarse sand, and that of phenol adsorption is: clay＞silt> fine sand > coarse sand. The results show that in the study of the balanced distribution of petroleum hydrocarbon contaminants in soil-water system, subdivision studies should be carried out based on the differences in content, structure and properties of each component.