Abstract: A pipeline pressure test will be challenged severely if the pipeline design coefficient is enhanced. Directing at safety problems in a pipeline pressure test with a design coefficient of 0.8, and through derivation of mathematical formulas, this paper establishes the relationship between pressure/pipeline diameter and temperature within an elastoplasticity range in oil and gas pipeline pressure test, analyzes the impact of design coefficient and residual gas volume in pipeline on the pipeline strength testing, puts forth key points needing attentions in the pipeline construction with the design coefficient of 0.8, and points out that with the given design coefficient, strict control of pipeline temperature rise shall be highlighted in the pressure test to prevent a pipeline diameter extension accident. The study results are very instructive for the pipeline construction with the design coefficient of 0.8.