Will the G value changes from one place to another place ? and what is the value of G ?

hey pavankumar, 

Gravitational constant (G) has an approximate value of 9.81 m/s², which means that, ignoring air resistance , the speed of an object falling freely near the Earth's surface increases by about 9.81 metres per second every second. This quantity is informally known as little g (contrasted with G, the gravitational constant, known as big G).

There is a direct relationship between  Gravitational constant and the downwards weight force experienced by objects on Earth.  However, other factors such as the rotation of the Earth also contribute to the net acceleration.

"G" is the universal gravitational constant and it doesnt change from place to place.. its constant through out the universe.. its often confused to "g" .. "g" means acceleration due to gravity ,it changes from planet to planet ,and also varies within the planet.... the value of "G" is found out to be 6.673*10^-11 m^3 kg^-1 sec^-2..

G is UNIVERSAL gravitation constant. The Universal suggests that its value is a constant throughout space. Although some theorists suggest that at very low speeds G can be modified to be a variable althought it has never been confirmed. It has a value 6.67x10^-11 Nm^2KG^-2