I heard something(long time ago) that Milky Way can be seen in South hemisphere only, is it true? If so, what is the reason?
The band of milky way is inclined by more than $60\deg$ to the celestial equator. Hence, it can be easily seen from the southern hemisphere.
In fact, the milky way center lies in Sagittarius (a southern hemisphere constellation), which means,
The Milky Way would look better in the Southern Hemisphere.