TO INVESTIGATE PLANT DISTRIBUTION SPECIES IN RANGELANDS OF MASHAD, THE PRESENT INVESTIGATION WAS CONDUCTED AT ABASABAD RANGELAND RESEARCH STATION DURING 2008-2009. SYSTEMATIC SAMPLING WAS CARRIED OUT AT TWO STAGES I.E. LATE SPRING AND LATE SUMMER TO COVER ALL POSSIBLE WEED SPECIES. POPULATION DYNAMIC INDICES INCLUDING FREQUENCY AND UNIFORMITY WERE CALCULATED. 19 SPECIES FROM 9 FAMILIES WERE IDENTIFIED. HULTHEMIA PERSICA, CARTHAMUS LANATUS, CENTAUREA DEPRESSA, AND CIRSIUM ARVENSE RESPECTIVELY HAD HIGHEST FREQUENCY. HULTHEMIA PERSICA WAS RECOGNIZED AS MOST INVASIVE PLANT.