A lot of work has focused on the development of zinc oxide thin film for the active layer for thin film transistors in recent years. In present article, the active layers for zinc oxide thin film transistors were first time prepared by r.f. Magnetron sputtering using a simply compacted 3-inch-diameter zinc oxide powder target, and the deposition parameters including O2/(Ar+O2) ratio, gas pressure and r.f. Power were carefully optimized. Thousands of zinc oxide thin film transistors with staggered-type or inverse staggered-type stack and various W/L ratios were fabricated and electrically characterized. A better result we achieved with normally-off TFT characteristics presents a saturated mobility of 25.7 cm2/Vs, a threshold voltage of 6.3 V, an on/off current ratio over 7.7×104 an off current less than 7.9×10-10 and a subthreshold slope of 1.2 V/dec. The TFT characteristics results can compete with those for the TFTs manufactured from high-temperature sintered ceramic target reported in literature thus far.