The geographical accessibility of public healthcare institutions is the key factor affecting the equity of healthcare services. Based on the hierarchical medical system and referral system in China, we analyzed the referral accessibility of hospitals in the Wuhan Metropolitan Development Zone. Before the implementation of the referral system, only 7.91% of the total communities met the accessibility standard for secondary and tertiary hospitals, which meant that there was significant inequality in high-level healthcare. Moreover, 5.4% of the total communities did not meet the accessibility standard for primary hospitals, which meant that there were insufficient primary hospitals. After the implementation of the referral system, the proportions of communities meeting the accessibility standards for the first-stage referral, second-stage referral and cross-level referral were 92.6%, 99.9% and 98.3%, respectively. The results show that the referral system has improved the accessibility of healthcare, but it has not completely solved healthcare inequality. The first-stage referral accessibility of healthcare services in the northern, western and eastern groups does not meet the accessibility standard, which is due to the inefficient layout of secondary hospitals. The Wuhan government should construct secondary hospitals in these groups and primary hospitals in the central urban area and the southeastern, southern, western and eastern groups.