This paper presents an in-depth comparison of the items and detailed assessment criteria of US’ WELL Building Standard System and China’s T/ASC 02-2016 Assessment Standard for Healthy Buildings (ASHB). Classification and statistics are made on each item of the two standards separately to analyze their different emphases, different weights, and different quantitative criteria. It is obvious that the two systems are identical with what should be a healthy building. A healthy building should be human-oriented living and working environments where human’s physiological and psychological needs are satisfied. However, they two systems show divergences on specific items and criteria, which are related to their social and construction practice. WELL is more performance-oriented, while ASHB is more experience-oriented. China ASHB could be improved from four aspects: Establish more performance criteria rather than one single measure; increase the demand for on-site inspection and testing; combine the concept of health into the consideration of whole life cycle of building design; and increase the impact of the standard on the post-occupancy stage of buildings.