A simple sample preparation method for determination of methamphetamine (MA) and its major metabolite, amphetamine (AP), in urine was developed using ionic liquid based headspace solid-phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS) with electron impact ionization working at selected ion monitoring mode. SPME fiber was prepared by coating ionic liquid (IL) on a bare silica fiber. Factors that affect extraction performance, including the base used, the concentration of the base, salt concentration, stirring rate, extraction temperature, and extraction time were investigated and optimized. The extraction performance of IL based SPME has been compared with the commercially available SPME fiber with 100um and 7um polydimethylsiloxane (PDMS) coating. The feasibility of the method was demonstrated by analyzing spiked urine samples donated by volunteers.