由于磷酸二氢钾在农业生产中的商品价值很高，同时其外观又与硫酸镁、工业废盐、碳铵、激素等十分相像，这就给一些不法商贩带来了制假售假的契机，辨别和购买到真正的磷酸二氢钾才是保证效果的基础。
　　Potassium dihydrogen phosphate has a high value in agricultural production, and its appearance is very similar to magnesium sulfate, industrial waste salt, ammonium carbonate, hormones and so on. This gives some illegal vendors a chance to make counterfeit sales. Identifying and purchasing real potassium dihydrogen phosphate is the basis of guaranteeing the effect.
　　1、价格上：正规的磷酸二氢钾200克售价在6-7元左右，市面上售价在4元以内的有的甚至是2元左右，显然是假货。
　　1. Price: The regular price of potassium dihydrogen phosphate 200 grams is about 6-7 yuan, and the market price is less than 4 yuan or even about 2 yuan, which is obviously a fake.
　　2、看包装：包装上会有醒目的“磷酸二氢钾”字样，执行标准为HG2321~92，总养分含量≥86%，其中P2O5≥52%，K2O≥34%。没有其他诸如“Ⅰ型、Ⅱ型、真品、微量元素、复合型、改进型”等字样，如此这般均可视为假货。
　　2. Look at the packaging: There will be a striking word "potassium dihydrogen phosphate" on the packaging. The implementation standard is HG2321-92. The total nutrient content is over 86%, of which P2O5 is over 52%, K2O is over 34%. There are no other words such as "Type I, Type II, genuine products, trace elements, compound, improved" and so on, which can be regarded as fake.

　　3、闻气味：真正的磷酸二氢钾是白色无味晶体，能闻到味道的都是假货，经过火烧、暴晒也无味道，有异味的说明是添加了激素或是假货。
　　3. Smell: Real potassium dihydrogen phosphate is a white tasteless crystal, which smells fake. After burning and exposure, it is tasteless. The odorous description is adding hormones or fake.
　　4、尝味道：真正的磷酸二氢钾是淡淡的咸味，取几颗放在嘴里，如果苦味可能是硫酸镁，如果很咸，可能是海盐冒充。
　　4. Taste: Real potassium dihydrogen phosphate is slightly salty. Take a few pills and put them in your mouth. If the bitterness may be magnesium sulfate, if it is very salty, it may be sea salt.
　　5、用火烧：取少量磷酸二氢钾放在铁片上，如果溶解成透明液体，冷却后凝固成半透明状物体，则是真品。
　　5. Burn with fire: Take a small amount of potassium dihydrogen phosphate and put it on the iron sheet. If it dissolves into a transparent liquid and solidifies into a translucent object after cooling, it is the real product.
　　6、水溶法：将纯碱放入磷酸二氢钾溶液中，如果出现大量气泡则为正品，如出现絮状沉淀则为假货。
　　6. Water-soluble method: Put soda into potassium dihydrogen phosphate solution, if there are a large number of bubbles, it is genuine, if there is flocculent precipitation, it is fake.