Abstract: For the shortcoming of abnormal thickness thinning in single point incremental forming (SPIF) technique, a compound forming method of bulging and SPIF (BF + SPIF) method was proposed. By using the methods of SPIF and BF+SPIF, the DC04 cold rolled deep drawing steel plates were processed into taper tables with forming angle of 55° and 65°, respectively. The effect of bulging on the thickness distribution of SPIF was discussed. In the composite forming method, the sheet metals were expanded to different heights (15, 25 mm), then a single point incremental forming method was employed. The results show that the tool path set with the equal residual crest height cause a deviation of axial feed in the initial processing, this deviation causes abnormal thinning in top area of the cone part; Bulging forming can effectively improve the thickness distribution and reduce the amount of abnormal thinning in SPIF forming parts so that the thickness fluctuates smaller within the theoretical range.