A reducing agent of sodium lignite water (wood pulp) is made by treating the liquid of a sulfate sludge in the form of modified chemical equation with a medium molecular weight and low sugar content. It uses additive concrete substances, contains a low ratio of ash, low gaseous content and strong ability to adapt with cement. The most important advantage of sodium lignosulfonate is that there is no precipitation in the liquid mixture that consists of high-performed naphthalene water reductant.