The invention relates to the technical field of optical fiber sensor medical devices, in particular to an OCT imaging compound micro probe integrated with optical fiber sensing multi-parameter measuring, and discloses a preparation method of the composite micro probe. The probe comprises a multi-core optical fiber, a side-hole optical fiber, a single-mode optical fiber and a multi-mode optical fiber which are sequentially welded, the multi-mode optical fiber comprises a central axis fiber core and an eccentric fiber core, the central axis fiber core and the fiber core of the single-mode optical fiber are welded at two ends of the fiber core of the side-hole optical fiber, photoetching FBG optical grating is arranged on the eccentric fiber core, and the front end of the eccentric fiber coreand the rear end of a side-hole air cavity on the side-hole optical fiber are aligned to further form an F-P air cavity; the front end of the multi-mode optical fiber is fused with a Bell ball. The structure of the probe is reasonable, sensitive units of FBG grating, F-P air cavity are integrated, a Bell ball focusing lens is fused through the multi-mode optical fiber, the definition of an OCT imaging observing image can be effectively improved, body tissue detecting imaging is conducted while measuring of parameters of temperature, pressure and the like is conducted, the overall structure iscompact, the size is small, and the probe has significant meaning in in vivo microvessel disease diagnosis and the like.