You can sue if the loan is overdue for more than one day, but generally the lender will first make a reminder. If the lender still refuses to repay the loan after the reminder, the lender will sue the borrower.

Article 188 of the Civil Code stipulates that the statute of limitations for petitioning the People’s Court for protection of civil rights is three years.

If the law provides otherwise, such provisions shall prevail. The statute of limitations shall be calculated from the date when the right holder knows or should know that the right has been damaged and the obligor knows.

If the law provides otherwise, such provisions shall prevail.

However, if more than 20 years have passed since the date when the rights were damaged, the People's Court will not grant protection. If there are special circumstances, the People's Court may decide to extend the period based on the application of the right holder. Article 192 stipulates that when the statute of limitations expires, the obligor may raise a defense of non-performance of obligations.

After the expiration of the statute of limitations, if the obligor agrees to perform, he may not use the expiration of the statute of limitations as a defense; if the obligor has performed voluntarily, he may not request return.