But by slowing his breathing he eked out an air pocket in front of his face until rescuers dug him out.
Wang said: "I knew the air wouldn't last, so I made myself relax and concentrated on my breathing by meditation.
"It was very still and quiet down there. I was surprised at how easy it was to focus my mind and achieve inner calm, even though I believed I was facing death.
"Later, it became very hot and suffocating. I thought I might not make it back to the surface. Then I heard the sounds of voices and digging, and suddenly I could see again. It was the longest two hours of my life."
A doctor at the scene in Ningbo, eastern China, said: "It's a miracle."
Wang was digging a 15ft ditch at a building site when a wall of earth collapsed, burying him alive.
He said: "I had my back to the wall. I didn't know it was falling until it was on top of me."
Workmates and 11 firefighters dug Wang out. One said: "As we went deeper, we used our hands to dig as we feared our shovels might injure him. Then we had to hold the soil back with fencing."