The former All-Black, 31, has been in imperious form with the boot for the table-topping Londoners and beat club-mate Chris Robshaw to the prize.
"I was very surprised and humbled to win this award," Evans said. "It is a great honour to be voted for by your fellow professionals. Just to be nominated was a huge honour in itself.
"I've got great respect and admiration for all the guys on the (Quins) team, and they've made my job easy this year.
"We've had a fantastic season so far, and hopefully we can finish the job at Twickenham on Saturday."
Robshaw was named as the runner-up, while Northampton centre George Pisi claimed third place.
Saracens fly-half Owen Farrell pipped Gloucester backs Jonny May and Freddie Burns to the young player award.
"It is a massive honour just to be nominated, never mind win this award, especially as it is voted for by your fellow professionals," Farrell said.
"These are the guys you play against week in, week out and all you want to do is earn their respect. It is so humbling."
England World Cup winner Jason Robinson was inducted into the RPA hall of fame.
Long-serving Saracens lock Hugh Vyvyan took the special merit award, Mat Turner was England sevens player of the year, while the Blyth Spirit award went to ex-Saracens player Alex Bennett.
Gilbert has released a new line of rugby cleats. The Gilbert Virtuo 8S is part of the exciting new product. Check it out.
The entire All Blacks apparel line has been updated for 2013/14. Check out the New Zealand All Blacks polo.
The Nike Tiempo is a solid rugby cleat and one of few styles still made from full-grain natural leather.
The Gilbert Blitz 8S rugby cleat is a great cleat at a great price of $69.99. Get a new pair of cleats today.
A cool looking all black rugby cleat with the high performance adidas is known for. Get in the Gear!
Wear the crest of the British and Irish Lions on your t-shirt. A great look for the summer.
The All Blacks Performance t-shirt is black with hints of blue from the training jersey. Very Cool.
The New Zealand All Blacks training jersey for 2013/14. Get in the Gear!
The USA Rugby Pro Alternate rugby jersey is perfect for any fan of the Eagles. Get yours to wear during the summer Test matches.
The NEW All Blacks 2013/14 jersey has arrived at World Rugby Shop. Dare to wear the colors of the All Blacks.