The invention discloses a nickel-based high-temperature alloy denitrification method. The method comprises the following steps that smelting raw materials are carefully selected, an Inconel690 alloy ingot is smelted by adopting a ZG-0.025 type vacuum induction smelting furnace according to the following technological parameters that vacuumizing is performed to reach 0.01Pa, 10-15kW is kept for 10-20min, and 20-25kW is kept until the ingot is molten; the vacuum degree is less than or equal to 0.05Pa, refining is performed for 10min, and electromagnetic stirring is performed; under vacuum, the power is reduced for freezing and deflating, heating is performed again, and repeating for 2-3 times is performed; high-purity argon is introduced in high vacuum, the temperature is adjusted, deoxidizing elements, namely silicon and aluminum and a volatile element, namely manganese are added, microalloying elements, namely niobium, titanium and molybdenum are added after electromagnetic stirring, and electromagnetic stirring is performed; and the power is reduced, pouring is performed, cooling is performed, an ingot is taken out, and a riser is cut off. According to the method, the technological process is easy to achieve, safety, stability and reliability are achieved, and the nitrogen content of the ingot capable of being obtained is less than or equal to 10ppm.