Abstract: Ultrahigh-resolution fourier transform ion cyclotron resonance mass spectrometry(FT-ICR MS) provides a average mass resolving power of more than 300 000 from 200 to 1 000 u. It is therefore now possible to positively identify the elemental compositions of petroleum by accurate mass measurement with an average deviation of less than 1 mDa from each assigned elemental composition. Compounds were sorting to “classes” (i.e., numbers of N, O, and S atoms), “types” (rings plus double bonds), and alkylation ((CH₂)_n) distributions. Selective ionization by ESI affords direct detection of polarity hetero-atom compounds (nitrogen compounds and carboxylic acids) in petroleum without pre-chromatographic isolation. Ion electrospray ionization(ESI) coupled with FT-ICR MS has become one powerful analysis technology for petroleum chemistry. This paper offers an introduction to the principles, generic applications, and data processing of FT-ICR MS in petroleum analysis, reviewed the main development on petroleum composition research, and the application of FT-ICR MS on organic geochemistry, oilfield chemistry, and petroleum chemical engineering. Although it is exist some problems on quantification, FT-ICR MS providing very good potential applications in petroleum and petroleum chemical industry.