There are various forms of dead-zone fault in power system, and how to remove the dead-zone fault quickly and correctly is related to the safe and stable operation of power system. This paper introduces several common dead-zone faults and causes of dead-zone faults. Then the deficiencies of typical dead-zone protection logic are analyzed thoroughly, including the operation time of relay protection and the scope of fault. It summarizes a variety of dead-zone researches status, and evaluates the advantages and disadvantages of various of relay protection schemes of dead-zone faults. Finally, based on the existing researches, some assumptions and suggestions are put forward for further research.