The invention provides a current and short-term reliability assessment method of a high-voltage transformer. According to the method, precise and quantized assessment is carried out on the current and short-term reliability of the high-voltage transformer by means of a fault tree and a fault mode assessment model through data obtained through all detection means of a current transformer, wherein the data include routine tour, special tour and preventive test data, diagnosis test data, foundation standing book information of equipment, past-year equipment defect and fault records and other data. After assessment, a mode that each maintainable component of the transformer can possibly have a fault and the fault generation probability can be obtained, and maintenance measures to reduce or prevent the fault mode can be formulated under guidance according to the correspondent relationship between the fault mode and inspection methods. A development trend of the short-term reliability can be predicted through an aging model of the equipment. The method can assess reliability of the high-voltage transformer, and has the advantages of being concise, easy to understand, precise, visual, quantized and the like.