The theses focus on the relationship between the underground banking and he illegal money transfer outside the country and the financial supports of the crime organizations. These theses present the historical perspective and the legal measures adopted by the international organizations and some governments to prevent the underground banking. The analysis result will be the main idea to compare, discuss and improve the legal measures of our country. According to this, there are three kinds of underground banking; Chinese Flying Money, Indian and Middle East Hawala and American Underground Banking. Thai Poey-Kuan is indicated as a Chinese one. The uses of this kind of instrument are to move money outside the country illegally without sending the reports to the Bank of Thailand and the Anti Money Laundering Office (AMLO). The source businesses that provide underground banking service are unregistered money exchange services, fake companies provide money exchange service, Casinos and the businesses that support the operations of the organized crimes. The solutions for this incident are increasing the officers’ investigation power to any suspected money laundering transactions by collecting the Suspicious Activity Transaction Reports from all of the institutions, promoting the use of special measures such as entrapment, wiretappings, controlled delivery and strengthening the investigative powers under the Currency Exchange Law and the Customs Law. Moreover, the activity of underground banking should be increased as the predicate offence of the new organized crime law of the country to prevent its operations and continuing the Free Money Exchange Enterprise Program to promote the legal dealers in business.
