The invention provides a heat preservation system for a cooling component of a converter valve and a method for obtaining height thereof. The system comprises a frost-proof shed arranged at the outer part of the cooling component of the converter valve and a heat transfer component arranged in the frost-proof shed; the heat transfer component comprises an air cooler and a cooling tower which are interconnected. The method for obtaining height is used to calculate air of an outdoor thermal insulation shed with different heights and construction cost; a curve graph of air reflux rate and the construction cost is plotted. The system prevents hot air circulation, and prevents heat transfer equipment and pipes frozen in winter, at the same time prevents sand blown into the heat transfer equipment affecting the normal operation of the system; an optimum height of a heat preservation system for the converter valve is effectively and accurately calculated by this method, and a balance point is found between the optimum height and the construction cost, a heat preservation system for the cooling component of the converter valve that satisfies design requirements and is economical and practical, and then the safe and reliable operation of the cooling component of the converter valve is ensured.