The invention relates to an evaluation method and system for the oil reservoir inter-well connectivity degree based on the multi-fractal. The method comprises the following steps that S1, production dynamic data of an injection and production well are read and processed, and time series of the production dynamic data is obtained; S2, the time series of the production dynamic data which are collected within a preset period after water injection is calculated through a multi-fractal algorithm, and multi-fractal spectrum parameters of the production dynamic data which are collected within the preset period after water injection are obtained; S3, the time series of the production dynamic data which are collected within a time span in the preset period after water injection is subjected to waveform character calculation to qualitatively evaluate inter-well dynamic connectivity; and S4, on the basis of qualitative evaluation of the inter-well dynamic connectivity degree, the multi-fractal spectrum parameters are used as injection and production dividing coefficients, and the inter-well dynamic connectivity degree is qualitatively evaluated through the injection and production dividing coefficients. The oil reservoir inter-well connectivity degree can be described in a fine-grained mode.