Abstract: In recent years,the trend of steel plate welded structure replacing cast iron is expanding. Welding bed has a very good application prospects due to the distinct advantages of shorter design and manufacturing cycle,higher efficiency,green environmental protection,higher flexibility and lower costs and so on. In this studies,the residual stress of different welded structure beds was tested. Results showed that the measured bed has a large amount of weld seam,and the maximum residual stress is 274. 4 MPa. The structural dimensions of the sliding saddle are relatively longer（ 620 mm×2 700 mm×252 mm）,which belongs to the short long piece. It has the longer weld seam and more steel plate,and the maximum residual stress is 300. 6 MPa. The weld seam and steel plate of the column are relatively less,and the structural size difference is smaller. The maximum residual stress of the column is 154. 9 MPa. The maximum residual stress of the foreign sliding saddle is 129. 8 MPa,which benefited from the excellent structural design and less and shorter weld welding seams. By optimizing the structural design,the layout of the ribs,the welding process,and reducing and shortening the weld seams,which is the basis of reducing the initial stress of welded structural machine tools and obtaining high-precision machine tools.