Traditional randomized controlled trial and real-world study have different advantages in internal validity and external extensibility, respectively. With the development of evidence-based health decisions, randomized controlled trial was no longer the only golden standard of interventional study, the research evidence of the real world was gradually involved in health decisions. This study mainly analyzed the requirements of evidence and actual application of evidence in the evaluation of the effectiveness of NICE in the UK. It was found that NICE still used the results of randomized controlled trials as a primary basis. Although real-world research has developed rapidly in recent years, it was limited used in health decision because of its bias by design and other factors. However, in recent years, real-world evidence has played a significant role in the field of innovative drugs or diseases that lack therapeutic drugs. With the improvement of real-world research in experimental design and data analysis, it is expected that it will play a more important role in health decision-making.