Is it Possible to link Value in Assembly (solidworks) ?

yeah... you can link the dimension values in assembly also.

just right click on annotations and select show feature dimensions.
tools --> equations select dimension of part.
then select another dimension and give necessary property
i.e dim. of sketch2=dim. of sketch1 /2

now if u change dimension of sketch 1 , sketch 2 will also be changed
just rebuild n see it..

thanks for such solution