The invention provides a preparation method for low-oxygen vanadium-nitrogen alloy. The low-oxygen vanadium-nitrogen alloy comprises the raw materials including, by weight percentage, 72-78% of powdery vanadium oxide, 20-26% of carbon powder and 0.4-1% of first catalyzer. The preparation method includes the following steps that (a) the raw materials are mixed and stirred uniformly according to the proportion of the formula and then subjected to dry powder squeezing for ball forming on a dry powder ball machine, and blanks are manufactured; (b) the blanks are put into a vacuum medium-frequency heating reaction furnace; (c) nitrogen is introduced into the furnace, and the following preparation technologies are carried under the protection of nitrogen atmosphere; (d) the temperature in the furnace continues to be increased to 1500-1700 DEG C, and the pressure of positive 0.05 Mpa is kept in the furnace; and (e) cooling is carried out until the temperature is 100 DEG C or below. According to the preparation method for the low-oxygen vanadium-nitrogen alloy, deoxygenation and nitriding are carried out in advance by using the iron-based catalyzer, that is, deoxygenation and nitriding are carried out in a low-temperature area; reaction is more thorough at high temperature, concentrated heat release in a high-temperature area is avoided, and the black core phenomenon of finished products, namely vanadium carbide, is greatly reduced.