Abstract: The activity law of the active fault F2 nearby Kizil Reservoir area in Xinjiang has a major impact on the safety of Kizil Reservoir. The analysis of short leveling long observation sequence striding the active fault F2 shows that the lower wall of the fault F2 continuously performed a ground tilting movement from south to north in the past 40 years. The ground tilting movement not only affected the calculation result of short leveling elevation difference, but also affected the calculation result of two parameters including horizontal twisting amount and sliding angle of the dislocation model. As a result, the evaluation of the activity of the active fault F2 cannot be objectively assessed. In this paper, the year-variable-rate of the ground inclining at the point of 12 m along the measurement line direction on the footwall of the active fault F2 is obtained to be about 0.224 mm/a (from 1979 to 2006). The the year-variable-rate is obtained using the trend analysis of artificial short leveling foresight reading long sequence from the first deformation monitoring station (FDMS). This rate of the ground inclining activity at the FDMS along the direction of measuring line between hanging wall and footwall is identified and verified with the surface Subsidence Rate isoline map on both sides of the reservoir area nearby the active fault F2. I They are respectively 0.03 mm/a and 0.07 mma-1(from 1991 to 2002). The results of the calculation and analysis from the horizontal twist amount and the sliding angle indicate that although the activities of the active fault F2 over the past 10 years have some close relationships with the reservoir sluice, the reservoir water infiltration down along the active fault, the river path change and the crustal movement, we still cannot conclude that the activities are being or have intensified.