The invention relates to an acidic 
soil conditioner and a preparation method thereof. The method comprises the following steps: preparation of a 
phosphate-containing 
solid from 
glyphosate waste liquid; preparation of a 
soil conditioner; 
granulation; 
drying; etc. Compared with CK, the pH value, effective 
phosphorus content and rapidly-available 
potassium content in soil of a capsicum area where the acidic 
soil conditioner is applied are increased by 0.44 unit, 21.60% and 33.87%, respectively; as for 
disease resistance, the incidence of capsicum anthracnose and the incidence of capsicum 
phytophthora blight are reduced by 17.83% and 26.21% compared with a control group, respectively; moreover, the contents of 
cadmium, lead, total mercury and total 
arsenic in capsicum fruit are reduced by 24.21%, 23.37%, 31.58% and 17.39%, respectively. According to the invention, recycling sustainable utilization of high-
pollution waste water in production of 
glyphosate is realized; the pH value of acidic soil is increased; and 
disease resistivity and harmful heavy 
metal ion absorbing capacity of plants are improved.