Expand the research field of phenolic compounds in reservoir geochemistry in order to play an important role in oilfield water injection development. Methods: To establish a separation and identification method for alkylphenol, the partition coefficient of phenolic compounds are calculated to establish the water oil ratio model. Results: The oil / water partition coefficient of phenol is 1. 98, and the average oil / water partition coefficient of C1 alkylphenol is 4. 60; The average oil / water partition coefficient of C2 alkylphenol is 12. 82; The average value of C3 alkylphenol oil / water partition coefficient is 54. 69.Conclusions: The oil—water gradient ratio experiment shows that the concentration of alkylphenol in crude oil gradually decreases with the increase of water content, and the concentration of C1 alkylphenol in D34 crude oil is low, which makes them more sensitive to water content than other alkylphenols, and there is an obvious correlation between m-cresol and p-cresol and water content, which has the potential application to indicate the water content in D34 crude oil. At the same time, this experiment also confirmed that there was a significant correlation between the oil / water partition coefficient of alkylphenol and the number of alkyl carbon; As the molecular weight of alkylphenol increases, the oil / water partition coefficient of alkylphenol increases gradually. Based on previous studies, a distribution model of alkylphenol series compounds was established. Under the ideal condition that the model is limited to the interaction between oil and water, the water oil ratio in the process of crude oil migration can be calculated by detecting the concentration and partition coefficient of alkylphenol.