A sprinkler assembly has a body, a base assembly, a wheel, a gear assembly, a discharging valve, a spraying head and a cover. The wheel is rotatably mounted in a wheel chamber in the base assembly and has a driving gear. The gear assembly has gear sets engaging each other. Each gear set has a driving gear and a driven gear coaxially mounted on the driving gear. The driving gear has a number of teeth different from that of the driving gear. The driving gear of one of the gear set engages the driving gear on the wheel. The discharging valve has at least one discharging hole. The spraying head is coaxially connected rotatably to the discharging valve and has at least one aligning hole selectively aligns respectively with the at least one discharging hole in the discharging valve.