Abstract: For the floating roof tank, single-deck is an important steel member and its deformation will hazard the safety of oil tank. The paper analyzes and demonstrates the deformation elimination method of tank deck, the stress and strain test of deck. The test content includes structure of floating roof, initial slope of deck installation, deck welding and stress and strain test of deck. Based on the analysis and demonstration results, the deck deformation repair method is put forward and implemented in an actual repair case. The repair result is satisfactory that the maximum deformation value of deck is less than 15mm, the deformation elimination rate of deck is more than 95%.