This research aimed to study 1) the preparation level of Thai Accountant Competencies and adaptation capabilities; and 2) Factor affecting on success in accounting profession after The Asian Economic Community. The samples consisted of 400 accountant which implement in many businesses. Data collected by using online questionnaire and employed convenience Sampling. Descriptive Statistics were used such as percentage Mean ( X ) S.D. and ranking. Pearson Correlation and Multiple Regression Analysis were also employed to analyze data. The finding results explained that most of antecedents were female finished bachelor degree of accounting and has experiences average equal 7.51 years (S.D. = 6.723). In their views They thought that accountants preparation level competencies especially improvement of knowledge and skills of professional accountant were rather than fair well ( X = 3.9129; S.D. = 0.44034) as same as adaptation capabilities ( X = 3.79; S.D. = 0.46631). Pearson Correlation was between 0.381 – 0.739 at the significance level α < 0.01. This findings also explained that the preparation level of Thai Accountant Competencies accounting experience attitude of implement accounting and adaptation capabilities have positive significance level at confidence level 99 percent (α < 0.01).