可控源音频大地电磁法(CSAMT)目前实际应用多以单个源采集标量数据为主,这种工作方式限制了CSAMT探测复杂地质构造的能力.随着CSAMT张量观测系统的推出和精细电法勘探的需求增多,CSAMT张量采集逐步受到重视.为了深化对CSAMT三维张量阻抗响应特征的认识,本文基于电场含源控制方程,采用交错网格有限差分法实现了CSAMT的三维正演算法;与二维CSAMT正演结果对比,验证了三维正演的正确性;设计了代表性三维地电模型,计算了标量和张量阻抗,对比和分析了标量和张量阻抗的响应特征. At present, CSAMT is mainly used to collect scalar data by a single source, which limits the ability of CSAMT to detect complex geological structures.With the introduction of the CSAMT tensor measurement system and the fine electric method In order to deepen the understanding of the response characteristics of CSAMT three-dimensional tensor impedance, this paper based on the field-source control equations, using staggered grid finite difference method to realize the three-dimensional forward algorithm of CSAMT; The correctness of 3D forward modeling is verified by comparing with 2D CSAMT forward modeling. Representative 3D geoelectric model is designed, scalar and tensor impedance is calculated, and response characteristics of scalar and tensor impedance are compared and analyzed.