The correct preposition to use in the sentence "Don't loiter the street" is "on."

1. "On" is used to indicate a specific location or surface where an action takes place. In this case, "on the street" refers to the location where the action of "loitering" occurs. It specifies that people should not loiter in the street.

2. "About" typically means concerning or regarding something, and it doesn't convey the idea of location or surface.

3. "Into" implies movement toward the inside of something, which doesn't fit the context of the sentence.

4. "Of" typically indicates possession or association, which doesn't make sense in this context.

So, "on" is the correct preposition to convey the intended meaning that people should not loiter in the street.