The invention discloses a method for synthesizing sunitinib, which comprises the following steps that: tert-butyl acetoacetate and acetylacetic ester are taken as initial raw materials, and tetra-substituted pyrrole is obtained through a nitrosification reduction reaction; then 2,4-dimethyl pyrrole-3-formic acid is obtained through the hydrolysis and is amidated; then an aldehyde group is utilized on position 5 of pyrrole through a Vilsmeier-Hacck reaction; and finally the obtained product and 5-fluorooxindole react to obtain the sunitinib. The method has low cost and simple operation, and is favorable for industrial production.