Henin, who also earned the honour in 2003, won 10 of the 14 tournaments that she started last year. She was unbeaten in 25 straight matches after falling to France's Marion Bartoli in the semi-finals at Wimbledon.
Despite that All-England disappointment, Henin took her total of Grand Slam singles titles to seven in 2007, with victories at Roland Garros and the US Open.
She became the first woman in history to earn more than five million dollars in prize money in one year.
Round-up: Sugiyama through
Serbian Ana Ivanovic, who won the prestigious WTA tier one title at Indian Wells last weekend, was named the most improved player.
The 20-year-old player added three titles to her resume in 2007 to take her total to five. She became the first Serbian to reach a Grand Slam final when she finished runner-up to Henin at the French Open.
American Lindsay Davenport was named comeback player of the year, after returning to the courts in September three months after the birth of her first child, son Jagger.
She won 13 matches with just one defeat to close out the year, capturing titles at Bali and Quebec City and returning to the top 100 (73) for the 15th straight year.
Hungarian Agnes Szavay, 19, won the best newcomer award after capturing her first two career titles at Palermo and Beijing. She jumped from 185th place in the world rankings to 20th.
Player of the year – Justine Henin
Doubles team of the year – Cara Black and Liezel Huber
Most improved player – Ana Ivanovic
Comeback player of the year – Lindsay Davenport
Newcomer of the year – Agnes Szavay
Karen Krantzcke sportsmanship award – Ana Ivanovic
Player service award – Liezel Huber
Henin handed tough road
Czechs move on in Hobart