A manufacturing method of a modularized leadframe, using a first mold set to contact and hold the upper surface of rows of multiple block leads, using a second mold set to contact and hold at least one selected surface of the lower surface of leads, the second mold set has a protruding part between each row of leads so that the upper surface of the protruding part be in close contact with the inner surface of the first mold set. The hollow space between the mold sets is then injected with packaging materials such that a leadframe structure having packaged and fixed leads therein and surfaces for wire-bonding and soldering is obtained. A packaging material filling space is formed in the leadframe after removing the first and the second mold sets.