Objective: To explore the rationality of taking the same discount rate for cost and health benefits in pharmaceutical economic research. Methods: Based on health related economic theory，the discussion was carried out from both positive and negative directions by combining theoretical analysis with formula deduction. Results: The dual attributes of consumption and investment as well as the diversity of health sources determine that the time value of health is different from the material capital; Keeler-Cretin paradox ignores the delay cost，the change of budget constraint and the inconsistency of time preference. Conclusion: It is necessary and urgent to estimate the unique discount rate of health benefits for improving the current pharmaceutical economic research.