Lending usury by car mortgage is illegal, as long as it is illegal. China prohibits high-interest lending, and the lending rate shall not violate the relevant provisions of the state. Automobile mortgage is a loan obtained from a financial institution or an automobile consumption loan company with the borrower's or a third person's car or self-purchased car as collateral. The purpose of loan with car as collateral is mainly for quick capital turnover. If there is no agreement on the payment of interest in the loan contract, it shall be deemed that there is no interest. If the loan contract does not specify the payment method of interest, and the parties cannot reach a supplementary agreement, the interest shall be determined according to the local or the parties' trading methods, trading habits, market interest rates and other factors; Loans between natural persons are regarded as interest-free.

1. It is legal for the interest of vehicle mortgage loan to meet the interest rate stipulated by law, and the interest whose interest rate exceeds 4 times the quoted interest rate of one-year loan market when the loan contract is established is not protected by law.

2. When the loan contract is concluded, the interest rate agreed by the borrower and the borrower shall not exceed four times the market quotation of one-year loan, and if the lender requests the borrower to pay interest at the agreed interest rate, the people's court shall support it. The interest agreement in excess is invalid.

Legal basis:

Article 680 of the Civil Code of People's Republic of China (PRC): It is forbidden to borrow at high interest, and the lending rate shall not violate the relevant provisions of the state. If there is no agreement on the payment of interest in the loan contract, it shall be deemed that there is no interest. If the loan contract does not specify the payment method of interest, and the parties cannot reach a supplementary agreement, the interest shall be determined according to the local or the parties' trading methods, trading habits, market interest rates and other factors; Loans between natural persons are regarded as interest-free.

Article 25 of the Provisions of the Supreme People's Court on Several Issues Concerning the Application of Laws in the Trial of Private Lending Cases: If the lender requests the borrower to pay interest at the interest rate agreed in the contract, the people's court shall support it, except that the interest rate agreed by both parties exceeds four times the market quotation of one-year loan at the time of the establishment of the contract.