"The pipeline would not make a meaningful long-term contribution to our economy," the president said.
The decision is expected to lead to the project's rejection by the Obama administration.
The president has increasingly signaled the $8 billion pipeline may not be approved.
A delay would almost certainly hand the decision for the $8 billion project to a future president.
The temporary injunction was prompted by a lawsuit from 70 landowners who don't want the pipeline on their property.