In this paper, we investigate the influence of deep level defects on the electrical properties of Ni/4H–SiC Schottky diodes by analyzing device current–voltage (I–V) characteristics and deep-level transient spectra (DLTS). Two Schottky barrier heights (SBHs) with different temperature dependences are found in Ni/4H–SiC Schottky diode above room temperature. DLTS measurements further reveal that two kinds of defects Z1/2 and Ti(c)a are located near the interface between Ni and SiC with the energy levels of EC–0.67 eV and EC–0.16 eV respectively. The latter one as the ionized titanium acceptor residing at cubic Si lattice site is thought to be responsible for the low SBH in the localized region of the diode, and therefore inducing the high reverse leakage current of the diode. The experimental results indicate that the Ti(c)a defect has a strong influence on the electrical and thermal properties of the 4H–SiC Schottky diode.