The intuitionistic fuzzy matter-element model with intuitionistic fuzzy decision information was proposed for the traditional matter-element theory which cannot be applied in intuitionstic fuzzy decision-making. It presented relative similarity to replace the traditional correlation function and then integrally described intuitionistic fuzzy matter-element multi-attribute decision-making method and its steps. An example was used to show the effectiveness of this method, especially it analyzed the multi-attribute group decision-making problem with unknown weight by using the projection method and intuitionistic fuzzy entropy to prove the practicability of this method.It is proved that the method presented here can offer a new approach to solve intuitionistic fuzzy multi-attribute group decision-making problems.