The amount of lignosulphonate in 6% of the 20 times the amount of ammonia, Pressure is 2.94~ 3.92MPa, Temperature of 180 ~ 250 ℃, Reaction time is 3 ~ 5 h, Air quantity is 5 ~ 10 L/min. In the first phase of carboxylic acid ammonium salt, low-level fatty acid amide and indole ring, pyrrole ring and other heterocyclic compounds; In the second stage condensation, make the indole ring of nitrogen content in more than 20%, thus obtained about 30% of the nitrogen content with a large number of indole ring plant hormones.

Another kind of plant hormone preparation method is as follows: The lignosulphonate after dilute nitric acid oxidation degradation , with ammonia neutralization, could produce orthoquinone plant growth hormone. This hormone for promoting plant seedling root growth, have significant effect to improve the survival rate of transplanting, make plant leaves more green, leaves larger, can make rice mature early, for rice, wheat, cotton, tea, bletilla crops has certain effect to increase production.