The main importance of the Compromise of 1850 is that it put off the secession of the South for at least a little while. Some historians believe that, by doing so, it gave the North’s economy enough time to become so industrialized and powerful that the South had little chance when the Civil War broke out.
The Compromise of 1850 was necessary because the North and the South were badly split on the issue of the lands that had been taken from Mexico in the recent war. California wanted to enter the Union as a free state, but that would have upset the balance between free and slave states. What could be done about this? Henry Clay fashioned a compromise. His compromise allowed California to come in as a free state but did not say anything about whether slavery would be allowed in the other territories of the Mexican Cession. The compromise included a number of other points, but these were perhaps the most important.
The Compromise of 1850 eased tensions between the North and the South for a while. Without the compromise, the South might well have seceded 10 years earlier than it did. This means that the compromise put the Civil War off by about a decade, possibly giving the Northern economy enough time to grow big enough to overwhelm the South when war broke out.