The widespread use of organophosphate flame retardants in commercial and industrial products hasled to their increased presence in the environment. The aim of this study is to optimize the extractionand analytical procedure for simultaneous determination of 15 organophosphate flame retardants(OPFRs) in air particle sample. The determination and quantification of OPFRs in air particle sampleswere performed using gas chromatography mass spectrometry (GC-MS) with selected ion monitoring(SIM). OPFRs in air particle sample were extracted by ultrasonic extraction with dichloromethane indark, followed by purification using florisil solid phase extraction (SPE) column and determination byGC/MS-SIM. The results show that this pre-treatment method is simple, quick, effective and less solventconsumption. The recoveries of OPFRs were from 88,2% to 104%, with relative standard deviation ofbelow 4,14%. This method showed a good precision and accuration in the determination of OPFRs inair particle samples. The method was then successfully applied for determination of organophosphateflame retardants (OPFRs) in indoor air particle samples collected in Thanh Xuan District - Hanoi.