what are some of main differences in the competition policy between
USA,Europe and Australia?

I don't think there is much difference. While wise economists realize
that moderate amounts of competition is good for the consumer and for
new business' trying to grow, (ultimately everyone except the world
dictator) government officials are typically eager to accept bribes
for supplying favoritism, which typically reduces competition. Lots of
laws are on the books but lawyers, and corrupt courts and bureaucrats,
tend to reduce the effectiveness of these laws in dealing with large
and powerful competitors. The rich and powerful internationalist have
gained power over all branches of government including the
legislative. The future looks dim unless we can reverse these trends. 
 Neil

Could you please analyse the regulation in these three places? and
Could you please tell me where I can get the regulation information
for USA, Europe and Australia?

perfect -

You should note that neilzero is not a Google researcher - you can
identify GA researchers because their handle is hyperlinked, as mine
is just above.

thanks,
ragingacademic