Four major in CPA refers to the four major professional disciplines in the CPA profession, namely accounting, auditing, tax and law. Accounting mainly refers to the work of collecting, recording and summarizing the financial data of an entity, and then analyzing and interpreting the results to provide financial information in the form of financial statements, reports and so on. Auditing mainly refers to the professional deployment and practice of auditing companies, enterprises, institutions and their financial activities, based on certain audit principles, to determine whether their financial statements are true and in compliance with the relevant laws and regulations. Tax mainly refers to the professional practice of taxation companies, enterprises, institutions and individuals, based on certain taxation principles, to determine their tax liability in accordance with the law and assist in tax filing, tax computation and other related services. Law mainly refers to the professional practice of jurisprudence companies, enterprises, institutions and their legal activities, based on specific legal principles, to determine the legal liabilities of all entities in accordance with the law and assist in handling legal affairs. In addition, four major CPA also refers to the four pillars of CPA profession, namely accounting theory, auditing theory, tax theory, and legal theory. It is through the comprehensive understanding and correct use of accounting, auditing, tax and legal knowledge that can truly achieve the goal of providing professional services for customers.