Sequence time domain reflectometry (STDR) is a common cable fault detection method, but the traditional STDR method can only identify the basic short-circuit and open-circuit faults, and cannot identify other types of faults with high or low resistance loads, which is limited in the application of accurate cable fault diagnosis. This paper proposes a normalized STDR analysis method for cable fault identification, which firstly determines the cable fault location according to the time difference between the autocorrelation peak of the input signal (m-sequence) and the cross-correlation peak of the input and reflected signals, then establishes a cable load impedance estimation method based on the normalization of cross-correlation peaks, and ultimately the fault type can be accurately identified through the estimated load impedance at the fault point. Cable fault experiments show that the error of cable fault location is less than 0.25%, and the correlation coefficient between the estimated cable load impedance and the true load impedance is more than 98.80%, which verifies the effectiveness of the proposed method. The proposed normalized STDR analysis method not only ensures the accuracy of fault location, but also realizes the accurate estimation of load impedance at fault point, so as to realize the accurate identification of different fault types such as short circuit, open circuit, high-resistance load and low resistance load, and breaks through the limitation of the traditional STDR method which can only identify the short circuit and open circuit faults.