Abstract: The earth fault in the high-voltage capacitor of direct current（DC）filter will greatly affect the security and stable operation of DC transmission system.The existing high-voltage capacitor earth fault protection of DC filter has the problems of poor selectivity,low sensitivity,difficult setting of definite value and so on.A new type of high-voltage capacitor earth fault protection criterion and protection scheme,which is independent of the system operating conditions,is proposed based on the requirements of DC transmission system and DC filter high-voltage capacitor protection.The proposed fault protection criterion and scheme is acquired by combining with the structural characteristics of H-type high-voltage capacitor and simplifying the earth fault model.The problems in the existing protection are solved by the proposed scheme.The actual ultra-high-voltage direct current（UHVDC）engineering simulation model is used to simulate the high-voltage capacitor earth fault.The validity and correctness of the proposed protection criterion and scheme are verified.