After constitutional revolution, the position of classes in society changed due to governmental reforms. Subsequently, such matter had influence on different aspects of life. The merchants and guilds, regarded as one of the most significant political– economical classes, had effectively economical– social functions. This class, influenced by governmental policies and global changes, was influential in currents of Iran. One of the concerns of Reza Shah's government was reducing the power of this class by controlling of guild system as a result of its substantial role in internal policies. Consequently, the reforms of government led to merchants and guilds' reactions such as strike, the suspension of market, complaint and demand. This article, based on documents and library studies, aims to investigate the status of guilds in political- economical structure of Iran at first decade of 14th century and the reasons of attention of Pahlavi I to them. The outcome of this research demonstrates that merchants had effective role in economical and political reforms in the decade of 1300s; however, the programs of Reza Shah's government for rehabilitation and foundation of absolute government limited the political and finical power of this class in economical field.