The Spaniard, two points clear of Ferrari's Michael Schumacher with three races remaining, stayed in the Renault garage and on the pit lane wall for the hour-long first practice session at Shanghai circuit.
Austrian reserve driver Alexander Wurz was quickest for Williams with a lap of one minute 35.574 seconds, 0.017 faster than Honda tester Anthony Davidson.
Neither will race on Sunday, leaving Honda's Jenson Button as the quickest race driver ahead of Schumacher -- who did a mere four laps on an overcast and muggy morning.
The German, seven-times world champion and with 90 career wins, has yet to score a point from two appearances in Shanghai.
Behind them came Switzerland's Neel Jani, France's Alexandre Premat and Germany's Sebastian Vettel -- test drivers for Toro Rosso, Midland/Spyker and BMW Sauber respectively.
Alonso, winner in China last year, habitually sits out the opening practice session to limit the mileage on an engine that must last for two races. He has a new and more powerful unit in China after a failure at Monza three weeks ago.
"I am very confident, as always," the Spaniard told reporters on Thursday.
"I think that for the last three races we should be very competitive...the car is really at maximum performance now, with no problems.
"We should be very quick. Now it is up to us and Ferrari to decide who is quickest," he added."
