Abstract: Aiming at the problem of the unqualified risk of strength and toughness performance test results of a wind power spindle product of a company, a series of physical and chemical tests such as composition analysis, performance test and metallographic examination were carried out on the product, and the obtained test data results were analyzed. The measures to effectively improve the strength and toughness of the product were analyzed and discussed. Comprehensively considering the user's needs and economic benefits, it was decided to adjust the composition contents of raw material of the product, and the vanadium element with a mass fraction of 0.15%~0.20% was added to the original 42CrMo4 steel compositions. The results show that the vanadium element can play the role of fine grain strengthening and dispersion strengthening in the steel, which improves the strength and toughness of the wind power spindle product and ensures the quality of the product.