In order to efficiently apply Thailand Securities and Exchange Act(“SEA”)to the highly dynamic market practices of Thailand’s capital markets,and to modernize the outdated data collection process and improve the regulatory framework,this thesis will present the suitable functioning approach to regulating stock manipulation by significant endeavor in researching Thailand Securities Law compared with the United States and China situations.Stock manipulation is a form of market abuse;e g spreading false information on the market,entering both a buy and a sell order for the same securities at the same price,or concealing ownership when disclosure is required by law.1 According to the fact that stock manipulation harms investor confidence and discourages investor participation in markets.This harms liquidity;increases trading costs and can increase the cost of capital for listed companies.Manipulation distorts prices,thereby reducing market efficiency and causes deadweight economic losses from distorted resource allocation.General speaking,“Stock Manipulation” is considered as one of economic crimes,which could bring the severe impact to the nation in the sense of the investment in the stock exchange.Consequently,the investors are unconfident in investment.This is an obstacle to develop The Thai Capital Market.Therefore,certain controls and special regulations needed to deal with this phenomenon in order to avoid distorting the minds of investors and confronting false prices.This thesis will start with examining the severity of stock manipulation in Thailand and stating the problems of the regulation of stock manipulation.For instance,the problem on the enforcement loopholes;Thailand’s securities laws need to be changed to close enforcement loopholes;the multiple steps involved in enforcement.Then,this paper conducts a comparative study between Thailand,the United States and Mainland China by analyzing their Securities Law and situations,in order to provide suitable regulation framework for stock manipulation in Thailand.This research will finish with a summary of the conclusions that can be drawn from the literature.At the time of writing this paper,Thailand was being in the process of amending Securities and Exchange Act 1992(the amendment No.5)for a long time.Eventually,the National Legislative Assembly passed SEA No.5 on September 1,2016.2 However,the SEA No.5 was on a rush of promulgation due to current government’s policy.The amendment process should be continue,and stay competitive in the globalizing environment.I am ensured that this study will be beneficial to Thailand Securities and Exchange Act and stock market participants.Research methodology of this study will begin with literature review by gathering and obtaining background information,then learning from black letter law of Thailand,the United States and Mainland China.