Objectives This study investigates the relationship between the prices of fixed-dose combinations (FDCs) and free-equivalent combinations (FECs) within China's National Reimbursement Drug List (NRDL). The focus is on comparing their price ratios.Methods We identified FDCs and FECs listed in the NRDL, along with recent bidding data. Publicly listed prices and characteristics of these medications were collected from Chinese government websites and commercial databases. Price ratios were calculated after adjusting for the active pharmaceutical ingredient's strength and dosage form, following the "Chinese Pharmaceutical Differential Pricing Rules."Results The analysis showed that the price ratios of FDCs to FECs in the NRDL averaged 1.11 ± 0.77 (Mean ± Standard Deviation). The price ratios varied significantly across different therapeutic areas, with the highest ratios observed in cardiovascular system drugs, followed by systemic anti-infective agents, digestive tract and metabolism drugs, and respiratory system drugs. FDCs in the negotiation catalog had lower and more stable price ratios compared to those in the regular catalog. The significant price reduction of FECs or FDCs due to the volume-based procurement (VBP) program also affected their price ratios.Conclusions The relationship between the prices of FDCs and FECs within China's NRDL is not clearly defined. These price ratios vary substantially across different therapeutic areas and drug categories and are influenced by the VBP program. These findings provide valuable insights for decision-makers on pricing strategies for newly reimbursed FDCs.