The disclosure provides a blocking element and its use in a protective structure. The blocking element includes a base and a first blocking plate. The base includes a surface and a recession formed downwardly towards the surface. The first blocking plate is connected to a first cross-connect part of the recession. The first blocking plate is used for pivoting on the first cross-connect part and includes a first blocking position and a first closing position in relative to the first cross-connect part. When the first blocking plate is at the first blocking position, a first blocking part of the first blocking plate protrudes from the surface. When the first blocking plate is pressed towards the recession to the first closing position by an external force, at least one portion of the first blocking part is contained in the recession.