Asperger syndrome is one of the autism spectrum disorders, and is classified as a developmental disorder that affects how the brain processes information. People with Asperger syndrome can show a wide range of behaviours and social skills, but common characteristics  include difficulty in forming friendships, communication problems (such as an inability to listen or a tendency to take whatever is said to them literally), and an inability to understand social rules and body language.

There is no cure and no specific treatment. Asperger syndrome doesn't improve, although experience helps to build up coping skills. Social training, which teaches how to behave in different social situations, is generally more helpful than counselling.
Typical adult symptoms

More males than females have Asperger syndrome. While every person who has the syndrome will experience different symptoms and severity of symptoms, some of the more common characteristics include:

    * Average or above average intelligence
    * Inability to think in abstract ways
    * Difficulties in empathising with others
    * Problems with understanding another person's point of view
    * Hampered conversational ability
    * Problems with controlling feelings such as anger, depression and anxiety
    * Adherence to routines and schedules, and stress if expected routine is disrupted
    * Inability to manage appropriate social conduct
    * Specialised fields of interest or hobbies.

The emotions of other people

A person with Asperger syndrome may have trouble understanding the emotions of other people, and the subtle messages that are sent by facial expression, eye contact and body language are often missed. Because of this, a person with Asperger syndrome might be seen as egotistical, selfish or uncaring. These are unfair labels, because the affected person is neurologically unable to understand other people's emotional states. They are usually shocked, upset and remorseful when told their actions were hurtful or inappropriate.
Being a partner and parent

Some affected people can maintain relationships and parent children, although there are challenges. Dutch research suggests that the divorce rate for people with Asperger syndrome is around 80 per cent.

A common marital problem is unfair distribution of responsibilities. For example, the partner of a person with Asperger syndrome may be used to doing everything in the relationship when it is just the two of them. However, the partner may need practical and emotional support once children come along, which the person with Asperger syndrome is ill equipped to provide. When the partner expresses frustration or becomes upset that they're given no help of any kind, the person with Asperger syndrome is typically baffled. Tension in the relationship often makes their symptoms worse.

its not easy to diagnose , i visited a special needs centre and many of the children looks just fine . 
experience is important 

can consult a pediatrician

edit : or psychiatrist  , think many hospital has it... no ?

Your should define your question more clearly, is that an established diagnosis for someone you know or you wish to seek second opinion from the internet? (which is not a good idea)

Asperger syndrome is very rare it is often a diagnosis of exclusion when the rest of common disease has been ruled out.

If you suspect some children to have very strange behaviour, consult a paediatrician first, before you go and see a psychiatrist.