Abstract: Objective To develop a method for determinating the octafluoropropane (OFP) content in human albumin micropheres loaded with OFP. Methods OFP content in the loaded human albumin micropheres was determined by means of gas chromatograpgy coupled with mass spetrum/selected ion monitoring (GC-MS/SIM). Results The calibration curve was linear within the concentration range of 40.92-16 368 nmol/L (R2=0.999 9). The limit of detection was 8.18 nmol/L, and the recovery?rate was (100.98±1.4)% (204 nmol/L), (102.63±2.29)% (2 046 nmol/L) and (97.5±2.2)% (8 184 nmol/L), respectively. The intra-day and inter-day RSDs were 0.6%-2.0% and 0.86%-2.3%, respectively. Conclusion The method of GC-MS/SIM is accurate, sensitive, precise and applicable for OFP determination in the microspheres.