The invention discloses a precise casting assembling and welding workbench. The workbench comprises a fixed seat, a scrap filter screen, a mounting sleeve, a motor, a reciprocating lead screw, an anti-skid welding pad, a protective glass cover, a sliding groove, a guide rod, a sliding connecting piece, a support, a transverse sliding connecting rod, a connecting block, a storage battery, a welding supporting component and hand-free welding equipment. The scrap filter screen is arranged on the fixed seat, the mounting sleeve penetrates through the fixed seat, and the motor is arranged on the mounting sleeve. The invention belongs to the technical field of casting machining, particularly relates to the precise casting assembling and welding workbench. The workbench effectively solves the problems that a welding workbench in the current market is few in protective measure and prone to hurting a human body, precise castings are higher in precision requirement, misoperation is prone to being generated during moving during fixed welding work, and the machining efficiency is affected, the welding protectiveness is high, moving and adjusting operation in the welding process is convenient, the precision is improved, and residues and chippings generated during welding are convenient to clean.