The invention belongs to the technical field of building materials and particularly relates to a sintered water permeable brick prepared with potash feldspar tailings as a main material and a preparing method of the sintered water permeable brick. The water permeable brick is prepared from, by weight, 55-75 parts of potash feldspar tailings with the granularity mesh number of 10-30, 15-35 parts of potash feldspar tailing mud with the granularity mesh number of 60-100 and 5-10 parts of a pore forming agent. The preparing method of the sintered water permeable brick comprises the following steps that firstly, water is added to mix the potash feldspar tailings, the potash feldspar tailing mud and the pore forming agent, and a mixture is obtained; secondly, the mixture is sealed and aged for 10-15 h; thirdly, the mixture is transferred to a brick making machine for pressing forming, and a water permeable brick blank is obtained; fourthly, the water permeable brick blank is dried; fifthly, the water permeable brick blank is transferred into a kiln for sintering and then cooled along with the kiln, and the water permeable brick is obtained. The water permeable brick is prepared from simple raw materials and is good in performance; the preparing method is simple, and the problems that the comprehensive utilization efficiency of potash feldspar tailings is low, and the environment is polluted are effectively solved.