Hou Debang wanted to clarify the Chaan Law and then try to reform and improve it. For this reason, he went to the United States again for inspection and soon obtained the patent specification of Cha'an Law. In response to the patent description, Hou Debang decided to conduct a comprehensive test on the new method of making alkali. After arduous exploration, the basic test of the Cha'an method was completed, and through layer-by-layer screening, the process conditions of the Cha'an method were fully understood.