The utility model discloses a calcium detects titrate stand annex, including bottom plate and light, the size of bottom plate is half the corresponding with titrate stand's, and the bottom plate is whole to be black, and the light is connected with the bottom plate through the lamp pole that can buckle. Technical scheme's calcium detects titrate stand annex more than adopting, arrange current titrate stand in on, can be used to the detection of calcium, can not change current titrate stand structure moreover in case influence going on of other experiments. In calcium survey was carried out to the EDTA method, green fluorescence closely shone down the light, observed fairly obviously simultaneously under black background, at the titration in -process, judged the disappearance that fluorescence is green very easily to can obviously reduce experimental error.