Abstract: The present invention relates to the field of rock mechanics technology, and provides a three-dimensional water absorption swelling multifunctional experimental machine and method for chemical swelling rock, comprising a triaxial high-temperature and high-pressure reaction chamber, the triaxial high-temperature and high-pressure reaction chamber is respectively connected with a confining pressure loading controller, a water pressure loading controller, a temperature controller, an axial pressure loading controller, a pH value monitor and a data acquisition and analyzer; the triaxial high-temperature and high-pressure reaction chamber includes a set of internal cavity and an external cavity, a sealing liner sleeve is provided between the internal cavity and the external cavity, a rock sample is provided in the internal cavity, a water-permeable pressure hoop is provided outside the rock sample, and the sealing liner sleeve is connected with a circumferential stress-strain sensor through a displacement structur