It is legal to stick the national flag on the car, but it shall not be used as a trademark or advertisement. The following is a detailed introduction to car stickers: 1. Posting requirements: Hanging the national flag reflects patriotism. Article 18 of the National Flag Law does stipulate that damaged, defaced, faded or substandard national flags shall not be hoisted. 2. Policies and regulations: Paragraph 3 of Article 13 of the Regulations for the Implementation of the Road Traffic Safety Law stipulates that the spraying, labeling or body advertisement of motor vehicles shall not affect safe driving. Therefore, car owners must choose standards and norms when posting flag-style car stickers on private cars, and at the same time, do not affect themselves and others to drive normally.