Abstract: In recent years, borehole-to-surface electrical methods have been widely used for monitoring water injection, gas injection, and hydraulic fracturing in oil and gas fields. However, conventional borehole-to-surface direct current resistivity methods rely on a single resistivity parameter and therefore have limited capability in distinguishing different fluid types and formation properties. In this study, the concept of time-domain induced polarization (TDIP) is introduced into borehole-to-surface direct current resistivity. A downhole distributed line source is adopted to approximate power supply from the perforated interval of a casing, and a surface receiving array is used to establish a joint borehole-to-surface DC-TDIP numerical simulation method based on an octree finite-volume mesh integrated with geological models. The primary-field potential and the time response of the secondary field after current shutoff are solved numerically, and gate voltages together with normalized apparent polarizability responses are obtained through time-window integration. Typical formation models with different resistivity and polarization parameters are designed for a variety of scenarios, and the apparent resistivity and apparent polarizability responses of both single-anomaly and multi-anomaly models are analyzed in combination with anomaly-difference signals and decay-curve characteristics. The numerical results show that the multiparameter responses of the borehole-to-surface DC-TDIP method can effectively improve the fluid identification capability of conventional borehole-to-surface direct current resistivity methods, distinguish anomalous bodies according to differences in polarization characteristics, and enhance the reliability of anomaly recognition in monitoring oil and gas field development processes.