The bill allows Oregon to pay for a new stadium using the income taxes of future team players and executives.
The baseball stadium finance plan had passed the House twice, but the Senate had the deciding vote.
Oregon is competing with Washington, and Northern Virginia to get the Expos, a franchise that MLB is relocating from Montreal next year.
Neither of the other two suitors has a stadium plan in place, which puts Oregon at the head of the race.
The upfront cash now available will pay a $150million chunk of Oregon's new stadium with the income taxes of future team players and executives.
The rest of the $350m stadium cost would come from a combination of private financing and other Portland-area taxes associated with the team although the details of where that money would come still must be defined.
Major League Baseball franchise the Expos could soon be moving to Oregon after the US Senate passed a bill clearing the way for a new stadium to be built in the state.
