The wily Romanian, the highest seed left in the draw after Serena Williams, Li Na and Agnieszka Radwanska were knocked out early, found perfect angles and defended superbly to counter Torro-Flor's powerful forehand in Paris.
"It's not a surprise because I'm more confident now in myself, and I feel the ball really good here at the French Open," said Halep, who has won more titles in the last 12 months than any other woman except Williams.
Halep, who has dropped only 11 games in three straight-set wins, will next meet American 15th seed Sloane Stephens for a place in the quarter-finals.
Stephens was in less devastating form than in her first two matches but she was still too strong for Ekaterina Makarova in a 6-3 6-4 win over the Russian left-hander.
The American has shown her consistency on the big stage by reaching the fourth round at six successive grand slam events, the only active woman to do so, but her ability to blow hot and cold on the WTA Tour has prevented her from climbing further up the rankings.
Makarova hit a return of serve wide to lose the first set and Stephens broke in the first game of the second set to set up the platform for a straightforward victory, even if she did have her serve broken later in the set.
Roland Garros has not been a happy hunting ground for Ana Ivanovic since she won the title in 2008 and the popular Serbian failed to break that jinx on Saturday as she lost 6-3 6-3 to Czech Lucie Safarova.
The 23rd seeded Safarova, who has a 5-2 record against the 11th seed having won their last five encounters, was never really bothered by Ivanovic's uncontrolled power.
"It's always tough matches with her. It had been a long time since I reached the fourth round here," said Safarova, who made it to that stage - and never beyond - in 2007.
She will face another champion in 2009 winner Svetlana Kuznetsova after the Russian 27th seed beat Czech fifth seed Petra Kvitova 6-7(3) 6-1 9-7 in three hours 13 minutes on court Philippe Chatrier.
Kvitova took two medical timeouts and came back from the first with a heavily strapped right thigh, but it did not seem to hamper her as she peppered the court with winners.
But her 65 unforced errors eventually cost her as she bowed out on the third match point.
Results from the French Open women's third round
6-Jelena Jankovic (Serbia) beat 26-Sorana Cirstea (Romania) 6-1 6-2
10-Sara Errani (Italy) beat Julia Glushko (Israel) 6-0 6-1
27-Svetlana Kuznetsova (Russia) beat 5-Petra Kvitova (Czech Republic) 6-7(3) 6-1 9-7
23-Lucie Safarova (Czech Republic) beat 11-Ana Ivanovic (Serbia) 6-3 6-3
15-Sloane Stephens (U.S.) beat 22-Ekaterina Makarova (Russia) 6-3 6-4
4-Simona Halep (Romania) beat Maria Teresa Torro (Spain) 6-3 6-0
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- Sports & Recreation
- Ekaterina Makarova
- Serena Williams
- Sloane Stephens
- Ana Ivanovic
- Lucie Safarova
- Agnieszka Radwanska