Why did the South not like the Compromise of 1850?

Answer 1

SOME in the South --mainly in South Carolina, Georgia, Alabama, and Mississippi -- objected to items in the compromise which:
1) admitted California as a free state, disturbing the balance of power between North and South in the Senate
2) negated some of Texas's land claims
3) abolished slave auctions in the District of Columbia -they regarded this as unconstitutional

http://en.wikipedia.org/wiki/Compromise_of_1850#View_of_Davis_and_Southern_Democrats

But note that Unionists in the South prevailed, and the Compromise was generally popular (as 'solving' the North-South dispute). Thus it is inaccurate to make the blanket statement "the South did not like" the Compromise.

And note that Northern Whigs ALSO objected to it, specifically to
1) the Fugitive Slave Act
2) the failure to apply the Wilmot Proviso (which would have BANNED slavery in territories, other than Texas, acquired from Mexico)

Answer 2

the compromise of 1850 balanced out the # of free states to slave states. the south wanted more slave states to have more power. plus california was a huge state to be free.