Emulsification and viscosity increase often occur during fracturing production of jimusar crude oil, which affects the normal production of crude oil. In order to clarify the cause of crude oil emulsification, the effects of crude oil composition, fracturing fluid composition and pH on emulsion stability and interface properties were studied; Petroleum acid was obtained by alcohol alkali extraction. The distribution and composition of petroleum acid were analyzed by high resolution mass spectrometry. The results show that guanidine gum fracturing fluid system is more emulsified than polymer fracturing fluid system. The main reasons for the emulsification of jimusar crude oil are as follows: first, there are many interfacial active substances such as naphthenic acid, aromatic acid and fatty acid in the crude oil; Second, the alkali and weakly alkaline formation water in the fracturing fluid components interact with the acidic substances in the crude oil for a long time to form soaps with strong interfacial activity; Third, strong stirring in the production process to promote crude oil emulsification. In order to solve the problem of emulsification and viscosity increasing, after adding 0.5% JN-1 viscosity reducing and drag reducing agent to the mixture of crude oil and fracturing fluid, the viscosity of the mixture decreases from 2232 mPa·s to 155 mPa·s at 30 ℃, which can effectively reduce the viscosity of the mixture. In view of the emulsification problem of jimusar shale oil, it is suggested to adopt alkali free sliding water system for fracturing development, and add viscosity reducer to the fracturing fluid, which is one of the effective methods to solve the emulsification and viscosity increase of jimusar crude oil after fracturing.