If the invoice that has not been deducted has been accounted for, it should be accounted for in the detailed account of tax payable-value-added tax payable-to be deducted, and then transferred to the input tax account after deduction next month. There are two situations in which the input invoice is not deductible, one is that there is a certificate that has not been declared, and the other is that there is no license to declare. In these two cases, State Taxation Administration of The People's Republic of China has specially taken corresponding measures: 1, the VAT deduction voucher obtained by the general VAT taxpayer has been certified or the information has been collected and reported, but the deduction has not been declared within the prescribed time limit; General taxpayers of value-added tax who implement the management of tax counseling period and general taxpayers of value-added tax who implement the management mode of "comparing before deducting" the special payment book for customs import value-added tax. If the results of the examination and comparison of the obtained VAT deduction vouchers are consistent, but the deduction is not declared within the prescribed time limit, which belongs to the objective reasons of real transactions and conforms to the provisions of Article 2 of this announcement, the taxpayer is allowed to continue to declare the deduction of its input tax with the approval of the competent tax authorities. If you encounter the second situation, you can try to find the reason from yourself and then take measures to solve it.