The invention relates to a large-size heterogeneous part cutting device. The large-size heterogeneous part cutting device comprises two cylindrical upright posts; a top telescopic mechanism is arranged at the top ends of the upright posts and is used for regulating the distance of the two upright posts so that the large-size heterogeneous part cutting device can be matched with to-be-cut components different in size; the two sides of the upright posts are each provided with a bearing screw assembly; each bearing screw assembly comprises a bearing and a screw rod which is inserted into the bearing; the top ends of the two bearing screw assemblies are each connected with a servo motor which is used for driving the screw in the corresponding bearing screw assembly to rotate; the periphery ofeach upright post and the corresponding bearing screw assembly is provided with a bucket holding device; and each bucket holding device moves up and down by taking the corresponding upright post as aguide rail by virtue of rotation of the screw in the corresponding bearing screw assembly. The large-size heterogeneous part cutting device provided by the invention has the advantages that (1) the large-size heterogeneous part cutting device can be transferred in a separated manner and can be rapidly assembled in a modularization manner; (2) the cutting efficiency is high and cuttings are easy tocollect; (3) an application method of the large-size heterogeneous part cutting device is simple and rapid, and a special control panel is provided; and (4) the large-size heterogeneous part cuttingdevice can be used for simultaneously cutting two sawn joints, namely an object can be cut into three parts by being sawn once.