mRNA differential-display reverse-transcription polymerase chain reaction (DDRT-PCR) is an effective and quick method to study gene different expression in the same cell under different physiological status and different stages of growth and development. In order to study immune response related genes in carp leucocytes, fluorescence DDRT-PCR was used to compare mRNA from leucocytes from peripheral blood of carp with LPA (50µg/mL), ConA (50 µg/mL) and PHA (50 revealed 3 cDNA fragments were immune response related genes which encoded proteasome activator complex PA28) and matrix metalloproteinase 13 (Mmp-13) of common carp. Bioinformatics analysis showed that the genes encoded by these different fragments were involved in various functions such as MHC class I antigen, signal transduction, translational control, apoptosis, degradation of the extracellular matrix. It is essential for further studying the mechanisms of these differentially expressed genes in fish.