The invention relates to a method of utilizing wastewater of marigold fermentation and dehydration to produce fertilizers. The method comprises steps such as linear equation establishment, neutralization system amplification, and the like. The problem that the cost for treating the wastewater of marigold fermentation and dehydration is high is solved. The wastes are converted into valuable resources. The effective components of wastewater of marigold fermentation and dehydration such as lactic acid, amino acids, and the like, are fully utilized. The provided method can solve the pollution problem, effectively solves the problem that the cost for treating wastes is high, provides an efficient liquid fertilizer for local crops, and greatly increases the crop output.