Abstract: To solve the problem that the model order is too high and difficult to solve when the traditional dynamic phasor sequence components (DPSCs) method is used for interharmonic analysis, we establish a grid-connected PV system model for interharmonic analysis based on dynamic phasor disturbances (DPDs). First, we deduce the dynamic phasor of a signal including interharmonic components, and define DPDs and dynamic phasor sequence components disturbances (DPSCDs). According to the known frequencies of interharmonics, DPSCs model is derived containing interharmonics from which the DPDs model is established based on superposition principle. DPDs model is used to represent the interharmonic interaction between AC and DC sides of the converter. Then, by calculating the steady-state operating point and solving the DPDs model, the calculation results of interharmonic components are obtained. Finally, the theoretical calculation results and simulation ones are compared to verify the validity of the model. The results show that the proposed model can be used to realize the interharmonic analysis of PV grid-connected system and order reduction. This model simplifies the calculation of interharmonic analysis and lays the foundation for the analysis of interharmonic emission characteristics and interharmonic suppression of grid-connected PV system.