Korea is carrying out weed quarantine by plant quarantine regulations including heat-treatment method to prevent the influx of exotic weeds. In order to confirm suitability for current heat-treatment criteria and find field-applicable methods which can completely devitalize quarantine weed seeds, the conditions for heat-treatment with/without 40% relative humidity were studied with 9 species among quarantine weed seeds and one weed species similar to quarantine weed. Dry heat-treatments had been tested under various temperatures and time conditions. All seeds were dead at the conditions of $95^{circ}C$ for 48 hours, $100^{circ}C$ for 36 hours, $110^{circ}C$ for 24 hours, $121^{circ}C$ for 4 hours and $130^{circ}C$ for 30 minutes. Heat-treatments at 40% relative humidity resulted in complete seed death at the conditions of $85^{circ}C$ for 36 hours and $90^{circ}C$ for 16 hours. The above results show that current heat-treatment criteria are not suitable for several quarantine weeds and these conditions could be applied as a quarantine method to prevent the influx of quarantine weeds along with agricultural imports. More specific conditions for heat tolerant species such as Picris echioides and heat susceptible species such as Cuscuta spp. are necessary and will improve plant quarantine process in devitalizing quarantine weed seeds with different heat tolerances.