Abstract: In order to solve the problem of expression of TEM response and definition of apparent resistivity at different station in the fixed-loop, the TEM response expression is given in this paper. The transmitting loop can be equivalent as some vertical magnetic dipoles, and the TEM response of fixed-loop is calculated as the sum of response of each vertical magnetic dipole. The response value of any point in the loop was calculated and the apparent resistivity expression was obtained. It was proved in calculation with half-space and 1D layered models. This research has theoretic and application significance.