The Kazakh never looked back in the second set rushing to a 5-0 lead as Muchova struggled with her serve, sealing victory and the 13th title of her career after one hour and 18 minutes.
Rybakina, who finished runner-up at Indian Wells last month, regained the title she won two years ago and drives off with a second Porsche sports car — the coveted prize awarded to the champion in Stuttgart.
"I was trying to read her serve, and in the beginning everything worked," Rybakina said.
"Then she started to serve a bit better, harder, and even knowing where the ball is coming and it was kind of on the racquet, but I was missing the shots. So it went pretty tight in the first set.”
"In the second, I was just trying to be more solid. I think the return improved. I was managing to see where she was gonna serve."
Muchova had lead Rybakina 2-1 in previous meetings heading into the title match having won their most recent clash on hard court in Brisbane in January.
Rybakina had a relatively smooth run this week dropping only one set and dispatching her toughest opponent world No. 6 Mirra Andreeva by the same score on Saturday.
The 29-year-old Muchova had eliminated French Open champion Coco Gauff in three sets in the quarter-finals but she was no match for two-time Grand Slam winner Rybakina.