Police say four people got into the property on Western Road in Goole around 7.30pm on Sunday 20 January.
They assaulted the homeowner, threatening him with a gun and knife, and stole cash, jewellery and watches from the safe, before stealing the keys and leaving in the homeowner’s white Range Rover.
The car was later abandoned on Canterbury Close in Scunthorpe around 8.40pm.
A spokesman for the force said: "We are appealing for anyone who saw anything suspicious on Western Road around the time of the robbery and for anyone who saw the white Range Rover between 7.30pm and 8.40pm before it was abandoned on Canterbury Close to call us."
Call 101 quoting log 443 20/01/19.