The product is a reflective warning shell which was placed on light poles. When the accident occurs, people can easily disassemble it to use. A reflective warning shell is consisted of two hollow semi-cylindrical shells. The reflective shell is bigger than the reflective triangle in the car, allowing car drivers behind being alerted at the first moment. In addition, the reflective shell can alert drivers in normal times, thus greatly reducing the chance of accidents. Through the product facilitated assembly and disassembly method with a good warning effect, the passers-by can get the best safe environment.