The invention discloses a pretreatment method for trace impurity elements on chlorosilane and polycrystalline silicon body surface metal. The pretreatment method is characterized in that a plurality of small-size independent sealed device main bodies are connected with corresponding telescopic arms 9; the small-size independent sealed device main bodies comprise inner-layer interfaces 13 and outer-layer interfaces 14; threads 21 matched with sample bottles 20 are formed in the inner-layer interfaces; sample bottles 20 of different sizes can be connected according to analysis items; buckles 22 are arranged on side walls of outer-layer threads and are clamped with a heat-preservation shade 15. By adoption of the sealed devices, pretreatment on trace impurity elements on chlorosilane, polycrystalline silicon body metal and surface metal is solved, samples can be treated in batch, the time can be shortened, and the maximum using of pretreatment resources is achieved.