The invention discloses a feedback control device and method for space lateral constrained loading of a test member. The feedback control device comprises a group of loading devices and a group of restraining devices, wherein the group of loading devices is arranged on one longitudinal side of the test member; each loading device is arranged corresponding to the nodes of the test member to apply load in the main loading direction to the nodes; the group of restraining devices is arranged on one transverse side of the test member to constrain the lateral displacement of the nodes; a first displacement measuring device is arranged on an opposite side of each restraining device; the first displacement measuring devices are used for measuring the actual lateral restraint displacement at the corresponding positions of the test member; a second displacement measuring device is arranged on an opposite side of each group of loading devices; and the second displacement measuring device is usedfor measuring the displacement in the actual main loading direction of the corresponding node on the test member. Through adoption of the feedback control device and method, the technical problems ofdifficulty in accurately reproducing the boundary conditions of component constraints in traditional tests and low accuracy and reliability of the test results are solved.