[taregg (OP)]

and what is the maximum velocity for low explosive is it 1000 m\s or 3000 m\s .......

[Bored chemist]

"does fuel classify to low explosive or high explosive"
No.
For example wood is often used as fuel but trees do not explode (unless that are hit in an electrical storm).
"and what is the maximum velocity for low explosive is it 1000 m\s or 3000 m\s"
No.
The limit is the speed of sound in the material.
http://en.wikipedia.org/wiki/Explosive_material#By_velocity
How come you didn't find that when you looked?

[taregg (OP)]

 i mean gas fule that  they use for cars air craft  big vehicles and gas cooking ..

[Bored chemist]

No.
It is not some arbitrary number.
It is the speed of sound in that material.
It will depend on what explosive you are talking about.

[taregg (OP)]

what you mean the material depeends of explosive ......can you explain more.......

[CliffordK]

According to Wikipedia, the difference between High Explosives and Low Explosives it the speed that the explosion travels through the material.

http://en.wikipedia.org/wiki/Explosive_material#By_velocity

If the explosion travels slower than the speed of sound, it is called Deflagration, and is a Low Explosive.
If the explosion travels faster than the speed of sound, it is called Detonation, and is a High Explosive.

Note, the speed of sound is about 340 meters per second, but is material and pressure dependent.

Keep in mind that Gasoline, Diesel, and etc are only explosive in the presence of an oxidizer.  Without an oxidizer (air), they are quite stable.

Nitroglycerin, on the other hand, does not require a separate oxidizer, and a sealed container can be detonated.

So, assuming a stoichiometric ratio of fuel/air.  What do we get?
According to Wikipedia. gasoline burns with Deflagration, or it is a "low explosive".
http://en.wikipedia.org/wiki/Deflagration#Applications

Here is some more information about detonation vs deflagration.
http://www.interfire.org/res_file/def_det.asp

However, that is only part of the story.
In an internal combustion engine, there is discussion of detonation (knocking) which is bad, and will damage the engine.
http://en.wikipedia.org/wiki/Engine_knocking#Abnormal_combustion

So, normally gasoline deflagrates in the presence of air (low explosive), but it can detonate (high explosive) in certain high temperature/pressure conditions.