There are some phenomena happen for automated fiber placement of sandwich structures, such as the honeycomb is prone to crush due to the compression of head, the bridge at the interface between the honeycomb and the bottom, the head contact with the honeycomb, etc. To solve the above problems, the automated fiber placement for honeycomb structures were investigated, which included the heating parameters and the compression force, the simulation of the placement, the stage of the honeycomb core, and the limit angle of the honeycomb, etc. The fiber placement path of sandwich structures were designed and the sandwich structures were manufactured, meanwhile the defects during the process were classified and analyzed, and solved experimentally. The investigation shows that the heating parameter would affect the layup ability of the prepreg, overheating can burn the prepreg. To assure the layup quality, the angle of the honeycomb is better to be less than 30 degree, and the honeycomb has a smooth connection with the bottom, the last but not the least, the size and the position of the honeycomb is crucial for the process quality.