Legal analysis: as the case may be. According to the relevant provisions of China's Civil Code, civil subjects can carry out civil legal acts through agents. If the wife agrees and authorizes, she can sign a loan car purchase contract in her name. On the contrary, a contract signed without the wife's authorization is invalid unless it is ratified by her.

Legal basis: Article 161 of the Civil Law of People's Republic of China (PRC), a civil subject may carry out a civil juristic act through an agent.

In accordance with the provisions of the law, the agreement of the parties or the nature of civil legal acts, civil legal acts that should be implemented by themselves shall not be represented.