This legal study is to compare the Electronic Transactions Act in Thailand(hereinafter 'ETA') with mainly other countries electronic transactions acts, such as UNCITRAL MLEC, UECIC, VETA, UCITA and Korea' Electronic Transactions Act The ETA is consisted of 6 chapters which included preamble and definitions. Each chapter's main point as follows. Preamble is related to the name, time of legal effect, scope and definitions. Chapter 1 is not only general principles of electronic transactions, required restriction in addition to specify the limit of application, documentation, evidential weight in reference to the data message, but also the conditions of offer and acceptance through data message, time and place of dispatch and receipt of data message, certification between origination and addressee. According to media-neutrality and the effectiveness security requirement of data message under the information system, legal certification is related to the exchange's declaration of intention, define about origination-addressee of data message. Chapter 2 is composed to provide expressly about the effectiveness security in electronic signature. Those contents are to compare the MLEC, UECIC and Electronic Transactions Act in Korea. Chapter 3 is related to legal definitions that present legal requirement about service relating electronic transaction which contents accept domestic law, the adequate requirement as eligibility, satisfied matter, self-reliance ratio of finance and other detail standard Chapter 4 is deal with the transaction which are public sector and those application requirements. And also this chapter are composed regulations about direct-indirect purpose of Thailand domestic electronic government.