If the emancipation proclamation ended slavery why does dr king say one hundred years later the negro is still not free?
Because of the crippling effect of segregation and discrimination
Slavery ended in a few states prior to the Civil War. Slaves were freed in Union Army controlled areas by the Emancipation Proclamation in July, 1863. The Proclamation was of dubious legality and only applied where Union troops were present. Slavery remained until the Civil War ended and the 13th Amendment to the Constitution was approved in 1865 finally and completely ended slavery.
Abraham Lincoln didn't actually end slavery in all states. He issued the Emancipation Proclamation in 1863, which led to the abolishment of slavery later on when he was assassinated. The Emancipation Proclamation led the Union to Victory because freed slaves were allowed to join the union army. (Look up: the 13th amendment which actually ended slavery for good.)