The invention relates to a preparation method of accurate pH test paper. An indicator is prepared by dissolving Metanil yellow, malachite green, acid turquoise blue, bromphenol blue, cresol red, m-cresol purple and bromocresol green in a 30% ethanol water solution. The preparation method comprises the following steps: previously impregnating base paper of pH test paper in the prepared indicator solution, and drying with heating steam of 95-105 DEG C at normal pressure. The preparation method of accurate pH test paper is simple in process, stable in product quality and higher in sensitivity and accuracy in comparison with the common accurate test paper, and the accuracy can be up to 0.2 level. Thus, the preparation method can be widely used in the fields of scientific research, industry, agriculture, environmental protection, medicine and food.