Even though , many flaws can be found in it . the imperfect tax credit system , various tax credit vouchers and the disjointed tax credit chain have made tax burden shift and tax payment run off . in the meanwhile , in the perspective of the current vat computation method , the more input tax payment is , the less tax payable will be , so increasing the amount of the input tax has become the major means of tax evasion and avoidance 但是，现行应纳增值税税额计算中的抵扣制度也存在明显的缺陷：抵扣制度不完善，抵扣凭证多样化，抵扣“链条”脱节，致使税负转移、税款流失；同时，由于在现行增值税税额的计算中，进项税额越大，应纳税额就越少，加大进项税额成为偷、逃税的主要手法。
Particular way is : it is plan tax basis with commodity sale , the tax rate consideration that provides according to tax law gives commodity to answer the appreciation the amount of tax to be paid of the burden , deduct next goods and materials is bought outside be being used to produce commodity place cost ( wait like raw material , fuel , running stores ) before pull current understands link already the value added tax of pay , the remaining sum after deducting is an enterprise to answer ratal 具体做法是：以商品销售额为计税依据，按照税法规定的税率计算出商品应负担的增值税额，然后扣除为生产商品所耗用外购物资（如原材料、燃料、低值易耗品等）在以前生产流通环节已缴纳的增值税，扣除后的余额为企业应纳税额。
