The invention relates to an assembling and adjusting method of an optical beam splitting system and a corresponding assembling and adjusting tooling, wherein the tooling comprises an optical platform, four positioning blocks, a first pad block, a second pad block, a third pad block, a fourth pad block, a first reference reflecting mirror and a second reference reflecting mirror, wherein the four positioning blocks are arranged on the optical platform and are used for positioning a beam splitting substrate; the first pad block is used for fixing a first collimated microbeam measuring pipe; thesecond pad block is used for fixing a second collimated microbeam measuring pipe; the third pad block is used for fixing a third collimated microbeam measuring pipe, a fourth collimated microbeam measuring pipe and a fifth collimated microbeam measuring pipe; the fourth pad block is used for fixing a collimated aligning telescope; the first reference reflecting mirror is completely collimated to images of the second collimated microbeam measuring pipe; the second reference reflecting mirror is completely collimated to images of the fourth collimated microbeam measuring pipe; and the optical splitting substrate is used for installing a first beam splitter, a second beam splitter and a third beam splitter. In the invention, the technical problem that the large batch production, assembly andadjustment of the beam splitting systems need to realize synchronization of assembly and replacement is solved, and the batch assembly and adjustment of splitting modules can be realized, so that theproduction efficiency can be improved.