Abstract: As a clean energy carrier with high heating value, hydrogen is expected to play an increasingly important role in future energy supply. In the long term, nuclear energy can meet the demand for clean, efficient and largescale hydrogen production. The very high temperature gascooled reactor can provide hightemperature process heat and is suitable for nuclear hydrogen production. The iodinesulfur cycle is a thermochemical watersplitting cycle, and is considered to be the most suitable for coupling with high temperature gascooled reactors to produce hydrogen. Currently, there are many technical researches on nuclear hydrogen production, but few economic researches. Economy is also an important aspect of nuclear hydrogen production. The economic analysis of nuclear hydrogen production has important guiding significance for further technical research and engineering construction. The present study uses hydrogen economic evaluation program (HEEP) to economically analyze the hydrogen production process of high temperature gascooled reactor coupled with iodinesulfur cycle. Firstly based on the features and functions, and calculation principles of HEEP, the levelized cost of hydrogen production was calculated by HEEP according to the discounted cash flow method. The lower the levelized cost of hydrogen production, the better the economic effect. Then the influence of technical parameters and chronological and economic parameters was analyzed. The results show that it is more economical to use nuclear power plants as the combined heat and power supply for hydrogen production plants than to use nuclear power plants only for heat supply while the power is supplied by external power grid. By optimizing the heat exchange network of the iodinesulfur cycle, the heat consumption of the hydrogen production process can be reduced, the hydrogen production efficiency can be improved, and the levelized cost of hydrogen production can be reduced. When the hydrogen production efficiency increases from 42.0% to 50.4%, the levelized cost of hydrogen production reduces by 12.0%. Extending the operating time of nuclear power plants can reduce the levelized cost of hydrogen production. The levelized cost of hydrogen production increases linearly with the increase in the capital cost of nuclear power plants and hydrogen production plants. The capital cost of nuclear power plants has a greater impact than that of hydrogen production plants. Moreover, when the discount rate and borrowing interest rate are at a lower level, nuclear hydrogen production is more economical. Finally, the economic effects of several hydrogen production processes were compared. In the case of a tax of 300 per ton of CO2, the high temperature gascooled reactor coupled with iodinesulfur cycle has the lowest levelized cost of hydrogen production. In general, the high temperature gascooled reactor coupled with iodinesulfur cycle is a relatively clean and economically promising hydrogen production process.