Two kinds of DMLC which have same mesomorphic unit but different spacer chain were used to toughen brittle DAIP. In order to get the best toughening effect, influences of curing procedure, especial the curing temperature on the formation of mesomorphic structure and miscibility between DAIP and DMLC were studied. The results showed that when DMLC was used to toughen brittle resins, the initiation curing temperature of the modified system was desired to be higher than it’s Ti and lower than DMLC’s Ti. When cured as the above procedure, the modified DAIPs showed macroscopic disordered but microscopic ordered structures. At the same time, most of modified DAIP systems showed great improvement of impact strength, as well as bend strength, modulus and heat resistance. The results also showed that when the DMLC with spacer chain was used, the modified DAIPs will have better toughness than DAIPs modified with no spacer DMLC. Fracture surfaces of the modified DAIPs were studied with SEM further. The results revealed that it was the ductile and strong DMLC mesomorphic domains to modify the toughness of brittle DAIP matrixes.