To investigate the electric field distortion characteristics of high-voltage direct current (HVDC) cables under typical defect conditions, a two-dimensional axisymmetric model of a 220 kV cable joint was developed using the multi-physics simulation platform COMSOL Multiphysics. Geometric models of representative defects, including air gaps, semiconductive particles, and metal spikes, were constructed based on common issues encountered during cable manufacturing, installation, and operation. Electric field simulations revealed that all types of defects caused significant distortion within the insulation system. Among them, metal spikes resulted in intense local field enhancement, with the peak electric field strength exceeding twice the value under normal conditions, thereby substantially increasing the risk of partial discharge and insulation breakdown. Parametric modeling was further conducted to analyze the influence of defect size on electric field distribution, highlighting the sensitivity of local field enhancement to defect geometry and position. The findings provide theoretical support and engineering guidance for insulation structure optimization, defect identification, and discharge risk warning in HVDC cable systems.