A new non-contact method for detecting overhead line single-phase to ground fault and short circuit fault in distribution networks is presented. The characteristics of horizontal magnetic field and vertical magnetic field of single-phase to earth fault are analyzed and the functional relationship of magnetic and fault current are derived. It is proven that horizontal magnetic field is much more suitable for detecting earth fault by comparing the different characteristics of the horizontal and vertical magnetic fields， such as detection position and signal intensity. The magnetic characteristics of short circuit fault are also analyzed. The method of detecting the short circuit current by inductive vertical magnetic field under line is proposed based on the functional relationship of vertical magnetic field and short current. The characteristics of non-contact fault detection are expounded on the accuracy， practicality， economy， safety and so on. Finally， simulations and tests verify the correctness of the proposed method.