To improve in-tube evaporation heat transfer at low quality, a novel evaporator based on efficient flow pattern global construction heat transfer enhancement mechanism is built, called the efficient flow pattern global construction evaporator (EFGE). The numerical analysis and experimental study of the thermodynamic performance of the EFGE are performed. Results show that the evaporation heat transfer coefficient (HTC) of the EFGE is 0.34–1.04 times that of a common parallel flow evaporator (PFE) and the pressure drop of the EFGE is only 80–116% of that of a common PFE at quality 0.9. The theoretical nonuniformity of the evaporation HTC between low- and high-quality flow is approximately 12–67%, which 55–72% of the pressure drop. The numerical analysis results are in good agreement with the finding that the EFGE has better thermodynamic performance than the PFE in terms of friction power reduction and minimum entropy generation number.