The present invention relates to a pool bottom cleaner which comprises a pump body which is provided with a motor at the inside and an impeller connected with a motor output shaft, a cleaning head which is arranged under a water inlet of the pump body and is provided with a connecting part which is communicated with the water inlet of the pump body as well as a handspike component which is connected with the outer surface of the pump body and can push the cleaner to travel in water. The pool bottom cleaner is characterized by also comprising a pontoon which is connected between the pump body and the cleaning head; the pontoon is provided with an axle hole which can be communicated with the water inlet of the pump body and a water inlet opening of the cleaning head respectively; and the pontoon and the cleaning head are connected in a demountable way. As the pontoon is arranged at the head of the cleaner, the pontoon can contain floating material, is convenient for installation and canavoid polluting a pool; the pontoon reduces the weight of the cleaner in water and is lighter for the operator to use; the cleaning head is changeable and is connected in a convenient pressing buckleform; and the connection structure is simpler and is very convenient for operation.