Barca have 92 points with two matches left, six ahead of second-placed Real Madrid who beat Getafe 4-0 on Tuesday, and Pep Guardiola's side hold the advantage in games between the two sides.
Seydou Keita headed the visitors in front after 28 minutes but a terrible mix-up between defender Gerard Pique and keeper Victor Valdes led to Felipe Caicedo equalising just before half-time.
A far from comfortable Barca held on for a point and can now focus on the Champions League final against Manchester United at Wembley on May 28.
"This isn't about today, it is about nine months of hard work, emotions and suffering. We deserved it today," striker David Villa told Spanish radio as he basked in his first league triumph.
"You can see how pleased we all are, above all because of all the work we have done."
Winning the title at the Ciutat de Valencia was particularly significant as it was where former coach Frank Rijkaard landed his first crown with Barca in 2005.
A 1-1 draw at Levante ended six trophyless years for the club that season and set in motion a cycle of success which Guardiola built on when he replaced the Dutchman in 2008.
Barca have now won five of the last seven Spanish championships.
The 40-year-old Guardiola, in his first top-flight coaching role, has picked up nine trophies in three years including three league titles, one European Cup and one King's Cup.
HIGH DRAMA
There was also high drama at the bottom of the standings, where 19th-placed Hercules (34 points) let slip a two-goal lead to draw 2-2 at home Real Mallorca and were relegated.
Real Zaragoza occupy the last relegation slot in 18th with 39 points, one behind Getafe and safety, after conceding a last-minute goal to lose 2-1 at Real Sociedad.
Osasuna pulled off a thrilling comeback to beat Sevilla 3-2 with breakaway goals from Kike Sola and Dejan Lekic in the last five minutes and they climbed to 14th on 44 points.
Valencia's 2-2 draw with Espanyol and Villarreal's 0-0 draw with Almeria meant there was no change in the race for the European places.
Valencia are third with 67 points and Villarreal fourth with 62 in the Champions League qualification spots, while Athletic Bilbao, Sevilla and Atletico Madrid occupy the three Europa League slots after all three lost.
HEAD IN HANDS
Barca dominated a cagey opening quarter until Xavi saw Keita's run from deep and flighted a long pass into his path. The Malian midfielder brushed off two defenders to power a header into the net.
Guardiola was not happy with his side and could be seen gesticulating on the touchline. He held his head in his hands when the defence gifted Levante the equaliser.
Pique tried to shield a ball back to Valdes under pressure fr
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