Disclosed are a feedblock multiplier with thickness gradient variation, a feedblock system, a method, and multilayer structure made by the method. The feedblock multiplier combines the functionalities of feedblock and multiplier conventionally used for producing the multilayer structure. The feedblock multiplier includes an input section for feeding fluid materials. A feedblock section is included for dividing the fluid delivered into multiple channels correspondingly. The fluids in the channels are segmented into two or more fluid segments by a segmenting section. The each fluid segment is delivered through corresponding channel-conversion section with thickness-gradient variation in the feedblock multiplier. Each channel-conversion section includes multiple channels with configurable positions. The fluids are then combined in a multiplier section for producing the multilayer structure with overlapped layers. The multilayer structure is outputted from an extruding section.