Solid phase micro extraction(SPME), which is solventless, flexible, inexpensive and sensitive, plays an important role in pretreatment. Stainless steel wire can overcome the breakable defects of traditional quartz fiber, so it has been widely used as SPME fiber matrix. In order to develop a sample preparation instrument which use less organic solvent, own high enrichment quality and automated, this paper studied and developed a gas purge syringe micro extraction system, which only use stainless steel needle as extraction phase. The stainless steel needle is etched by hydrofluoric acid, without any coating adsorbent material. It is an automated and open system which contains heating sample matrix, condensing extraction phase and inert gas purging. Under optimized parameters, extraction experiments were performed, for enriching volatile and semi-volatile target compounds from the sample of 15 PAHs standard mixture. GC-MS analysis results indicated that a high enrichment factor was obtained from the system. The results demonstrate that system is potential in determination of volatile and semi-volatile analyzes from various kinds of samples.