The 33-year-old Park, a six-time winner on the LPGA Tour who won the Vare Trophy for low scoring average in 2004, had battled injuries later in her career.
"I've had a wonderful career out here," Park, 33, told Golf Channel after her second successive round of three-over 75 at Locust Hill Country Club in the year's second women's major.
"I've had my ups and downs. I've had my surgeries. Honestly, it's not turning around and I'm ready to try new things. Ready for a new phase in life.
Park, who moved to the United States from South Korea at age 12 and was named the College Player of the Year while at Arizona State University, has not won an event in eight years and said dealing with injuries had been a great frustration.
"It's my own fault for not taking care of my body," said Park, who is planning on getting married. "I struggled with back pains since I was a junior golfer but never really dealt with it until I had to go through two surgeries and three years off on tour."