HEDP was synthesized in medium-test (50L) by one-step reaction with industrial grade acetyl chloride, phosphorous acid and n-butyl alcohol. Then, a low phosphorus water treatment agent HDW-2 was obtained by combining HEDP with zinc sulfate, sodium molybdate, sodium gluconate. On the basis of its scale and corrosion inhibition properties, a linear relationship model between HDW-2 dosage and scale and corrosion inhibitor rate was set, and trial on site for a period of one month in some enterprises in shandong province. The results showed that the scale inhibiting rate was up to 96.3% when the dosage of HEDP was 15 mg/L(equal to 2.02 mg/L PO43-) and the corrosion inhibiting rate was 95.2%, the corrosion rate was only 0.028 mm/a when the dosage of HEDP was 64 mg/L(equal to 8.49 mg/L PO43-). Adsorption law of HDW-2 followed the Langmuir isotherm adsorption model, based on it the dosing models (for anti-scaling) and (for anti-corrosion) were set. After a month of field test application, it showed that the system run stability, pH was maintained between 8.07-8.57, electrical conductivity was maintained between 1950-2690 μs/cm, calcium hardness total alkalinity was maintained between 892-1080 mg/L, chloride ion was maintained between 183-287 mg/L, total Fe was maintained between 0.12-0.32 mg/L, the corrosion rate <0.04 mm/a, total phosphorus (PO43-) was maintained between 3.37-7.55 mg/L. The water quality indicators had reached the requirement of party a's assessment indicators, thus the water treatment reagents HDW-2 has a certain market prospect and value for industrial application.