The invention belongs to the technical field of concrete material durability detection equipment, in particular to a concrete water absorption rate testing device in a parallel sustained load action direction. A main body structure comprises a concrete test piece, a lower steel plate, a steel hoop, a steel cylinder group, an annular plate, a silica gel tube, an upper steel plate, a threaded rod, aspring, a nut, a water supply tank, a water injection pipe, a water injection valve, a water storage tank, an air pressure balance hole, a silica gel hose, a water outlet pipe, a mass sensor, a multi-channel data acquisition device, a computer and a strain gauge. The concrete test piece is loaded by using the steel cylinder group so as to realize a concrete water absorption amount test in the parallel sustained load direction, the surface water absorption rate of concrete in the parallel sustained load direction is measured while a continuous load action is applied; the coupling problem of the load action and the concrete water absorption process in the parallel sustained load direction can be solved, and a foundation is laid for researching a concrete adsorption influence mechanism and change rule of the sustained load direction; the device is simple in structure, easy and convenient to operate and friendly in application environment.