Swiatek defeated the Russian ninth seed 6-3, 6-2 in the first meeting between the two players.
The four-time Grand Slam champion is yet to get past the fourth round of Wimbledon, which starts on Monday, although she was junior champion at the All England Club in 2018.
On Thursday, the Pole broke Blinkova once in the first set and twice in the second.
Throughout the match she demonstrated a notable improvement to her serve compared to when she crashed out to Alize Cornet in the Wimbledon third round last year.
"I'm happy that I can play such solid tennis," said Swiatek, who is using the extra week before Wimbledon after a schedule change to play on grass for the first time this season.
"Usually there's not much time to play on grass.
"I'm pretty happy that I used that time 100 percent between Roland Garros and Wimbledon...
"Hopefully I can play like that for the next two weeks."
The 22-year-old has won three of the past five Grand Slams but has never won a tournament on grass, despite claiming 14 trophies in her young career.
"I wouldn't put myself close to being an expert on grass but I'm making progress and that's the most important thing for me," Swiatek said.
"The time here really helped me. Every year I feel like it's easier to get used to the conditions."
World number 39 Blinkova made the final herself at the Wimbledon junior tournament eight years ago, but has never got past round two as a senior.
Swiatek will next face Italian Lucia Bronzetti, who defeated French eighth seed Varvara Gracheva 6-4, 6-3 earlier on Thursday.
American Emma Navarro also reached the semi-finals after her opponent Rebeka Masarova pulled out in the second set due to a knee injury, while trailing 7-6 (7/2), 1-1.
In Thursday's last quarter-final, second-seeded Russian Liudmila Samsonova takes on Czech Katerina Siniakova.
