Paes and Dlouhy, winners of French Open and US Open last year, needed just 42 minutes to score a 6-3, 6-0 victory over the Spaniards, dropping just nine points in the second set.
Meanwhile, fourth seeds Mahesh Bhupathi and Max Mirnyi came through a close battle with French duo Arnaud Clement and Jo-Wilfried Tsonga 6-4, 6-7(5), 10-4 in one hour and 38 minutes to reach the semifinals, where they play Mariusz Fyrstenberg and Marcin Matkowski.
If Bhupathi and Mirnyi win their semifinal match, they will meet Paes and Dlouhy in the final.
The Indo-Belarusian duo, which reunited at the beginning of 2010, is through to its first semifinal since featuring in the final four of the 2004 BNP Paribas Masters in Paris.
The 2002 US Open champions are bidding for their seventh title together and their fifth ATP World Tour Masters 1000 trophy. Their most recent triumph together came at the 2004 Internazionali BNL d'Italia in Rome.
The 35-year-old Bhupathi is aiming to reach the Miami final for the second time in three years after finishing runner-up with Mark Knowles in 2008.
The 32-year-old Mirnyi is defending champion in Miami after lifting the trophy last year with Andy Ram and is chasing his fifth title.