In medical research, pilot and feasibility studies are conducted to reduce the uncertainty of future main trial and enhance its overall quality and probability of successful completion. The objective of a pilot and feasibility study is to answer whether the main trial can be performed, should be performed, and if so, how. Due to the tremendous resources, time, and funding required for a phase Ⅲ clinical trial, conducting a pilot and feasibility study is generally a pivotal step. While pilot and feasibility studies are gaining increasing attention in clinical research, efforts are largely required to promote the dissemination in China. Therefore, in this article, we briefly introduce the concepts of a pilot and feasibility study, its importance to the main trial, and current practice. Examples are also provided to help illustrate the introduction.