增值税是对从事销售货物或者提供加工、修理修配劳务以及从事进口货物的单位和个人取得的增值额为课税对象征收的一种税。增值税设计的基本原理是：一、按全部销售额计算税款，但只对货物或劳务价值中新增价值部分征税；二、实行税款抵扣制度，对以前环节已纳税款予以扣除；三 Value-added tax (VAT) is a kind of tax levied on taxable objects for value-added items obtained by units and individuals engaged in the sale of goods or the provision of processing, repairs and repairs, and import goods. The basic principle of VAT design is: First, calculate the tax amount according to the total sales amount, but only add tax to the value added in the value of goods or services; Second, implement the tax credit system, and deduct the tax payment for the previous link. ;three