The invention belongs to the field of labeling and relates to a test tube labeling machine. The test tube labeling machine overcomes the problem of low efficiency of the existing semi-automatic labeling device in the prior art. The labeling machine is mainly composed of a main body mechanism, a base, a loading mechanism and an unloading mechanism, wherein the main body mechanism comprises a main roll mechanism, a supporting plate mechanism, an auxiliary roll mechanism, a rotating shaft and a compression roll mechanism, all of which are orderly fixed on a base plate; the base is composed of a substrate, a box fixedly connected with the substrate, and a loading cabin support, a motor support and an unloading cabin support, the three of which are fixed on the box; the loading mechanism is composed of a loading cabin fixed on the loading cabin support, a baffle plate mechanism fixed on the motor support, and a push plate mechanism; the unloading mechanism is composed of an unloading cabin fixed on the unloading cabin support, an XY worktable fixed on the substrate and a test tube holder placed on the XY worktable; the main body mechanism also comprises a locking mechanism and a clamping mechanism. The test tube labeling machine is capable of labeling test tubes different in diameter and is simple in structure, convenient to adjust and convenient to operate.