A thermistor chip is provided, which includes a thermosensitive ceramic substrate, a surface electrode and a bottom electrode. The surface electrode and the bottom electrode are respectively arranged on the two surfaces of the thermosensitive ceramic substrate. The surface electrode is a silver layer. The bottom electrode consists of a silver layer, a titanium-tungsten alloy layer, a copper layer and a gold layer, laminating on the thermosensitive ceramic substrate in turn from inside to outside. A preparation method thereof is also provided. The thermistor chip can meet the requirements of both solder paste reflow soldering and wire bonding process simultaneously, and has the advantages of good bonding effect and high temperature resistance, high reliability and high stability.