As a new technology, magnetic target detection technology has many advantages, such as low cost, fast and reliable, low environmental impact and so on. At present, there are many kinds of magnetic target detection techniques based on the total magnetic field intensity, magnetic field vector, magnetic gradient tensor, etc. The magnetic gradient tensor is the current research hotspot because it contains more abundant information. However, in most researches, the influence of carrier attitude change on location result is neglected, which affects the practical application of tensor method. Therefore, this paper focuses on analyzing the influence of the change of attitude angle of the carrier on the results of the STAR method that based on the magnetic gradient tensor. The simulation analysis is carried out when the attitude change of the carrier is ignored and the attitude change of the carrier is taken into account, and the attitude angle measurement error is at most one degree. It is found that the positioning error of magnetic target is greatly affected by the carrier attitude change, and the positioning error percentage is up to 191.7%. Therefore, it is necessary to measure the attitude angle and convert the coordinate when the tensor method is applied in practice. However, the carrier attitude change basically does not affect the estimated distance between the measuring point and the magnetic target, and the error percentage fluctuates in a small range of 0–3%, which provides a good idea for improving the positioning accuracy in the practical application of tensor method.