Rhondda's Chris Bryant won a House of Commons ballot to bring forward his own bill which has a good chance of becoming law.
Ideas include civil partnerships for straight couples, harsher penalties for attacks on emergency services, and curbs on advertising unhealthy food.
"I want my constituents to help me make my mind up," he said.
Mr Bryant launched his shortlist at Ysgol Gyfun Cymer on Thursday as a means of engaging people in the political process.
"There are hundreds of things I would like to change in this country, but I have to choose one," Mr Bryant said.
"What I have said is that I want my constituents to help me make my mind up.
"I'll be putting six ideas on my website, and people will be able to go and vote, 1,2,3,4,5,6, and I promise I will present either the top or the second top."
The ideas are:
A Welsh MP is asking people which new law they would like to see from a shortlist of six.