Light hydrocarbon geochemical field is one of the manifestations of hydrocarbon.Geochemical field is composed of field source and field effect.The field source is the material base of light hydrocarbon remigration;the field effect

which is effected by the solubility of formation water and country rock property

is the interaction of light hydrocarbons and soil substrate.During migration

light hydrocarbors possess the behaviour of dynamical equilibrium and divergence

the migration direction is determined by the contrast between passages and resistance.It is suggested that

in geochemical exploration

one should not only consider the property of field source

but also the preservation state

the composition and contents of light hydrocarbons

and carry out comprehensive analysis in time-space.