Alleviating catastrophic health expenditure () is one of the vital objectives of health systems, as defined by the World Health Organization. However, no consensus has yet been reached on the measurement of . With the aim of further relieving the adverse effects of and alleviating the problem of illness-caused poverty, the Critical Illness Insurance () program has been operational in China since 2012. In order to verify whether the different measurements of matter under China's program, we compare the two-layer models built by using the basic approach and the ability-to-pay () approach at a range of thresholds. Exploiting the latest China family panel studies dataset, we demonstrate that the basic approach is more effective in relieving for all insured households, while the approach works better in reducing the severity of in households facing it. These findings have meaningful implications for policymaking. The program should be promoted widely as a supplement to the current Social Basic Medical Insurance system. To improve the program's effectiveness, it should be based on the basic approach, and the threshold used to measure should be determined by the goal pursued by the program.