Is the Sunday Law againts the US constitution?

It definitely seems to break the First Amendment to the Constitution in that it favors the religious practices of one religion over others. However, local "blue laws" prohibiting sales of certain liquors or other items on Sunday survive throughout the United States (1). Here in Colorado (and 13 other states), you can't buy or sell a car on Sunday - a measure actually demanded by car dealers themselves to provide a day of rest without fear of losing sales to the competition, not as a show of religious piety.

The Supreme Court of the United States has upheld blue laws, noting that while the origin of many state blue laws was to enforce attendance at Church, now these laws were intended to serve "to provide a uniform day of rest for all citizens" on a secular basis and to promote the secular values of "health, safety, recreation, and general well-being" through a common day of rest. If this secular day of rest falls on the Christian day of rest, it doesn't reduce its effectiveness for the state's purposes or promoting a uniform day of rest or prevent those of other religions from observing their own holy days. (1)

So really, the difference between our blue laws and the German Sunday Law is a matter of degree, not a fundamental difference. The Germans have enforced their Sunday Law on much the same basis as the US Supreme Court has - to promote rest for the public for non-religious reasons (and in one case, to hamper the Church of Scientology from recruiting on Sunday as the Germans regard it as a business, not a religion) (2).

Are you referring to the old "Blue Laws" when shops could not sell some items on sunday? This is a local issue. These laws were passed to protect small business since they were usually operated by a sole proprietor and needed to take at least one day off a week. My old town voted against the laws when the chains came in. This killed a lot of the main street stores.

They used to have what they called "blue laws" which prevented businesses from operating on Sundays. I believe they were just reversed on the state level and that the Supreme Court did not interfere with the states' and local governments' rights to make such laws. Many states still restrict or prohibit liquor sales on Sunday.

There is a lot of laws that were against the constitution yet they past them anyway what make u think they would not with this one. The Bible must be fulfill so this will be done if u like it or not.Sorry for those who think it wont happen.

It's a local issue. I went to a two-community school north of Milwaukee, Wisconsin. The other community and the one of similar heritage and religion to the north both had blue laws. It's not a big deal.

What is a sunday law?

I think it's a states' rights issue. These laws are mostly implemented by cities and counties. I wouldn't be concerned about it.