To detect mRNA expression levels were very useful not only for the biological studies but also for the progress of medical therapy. Furthermore, mRNA transcription suppression caused by antisense also clearized and made possible the speedy result of the cell biological investigation. We created primer design protocol using fuzzy deducing theory, because the most of the traditional computer protocol succeeded less than 20%. The 90% of our primers functioned after following checking (1. GC Contents Check; 2. Homologous Check: [versus a.: GAPDH, b: Profilin,; 3. Self-Homology Check;). We also added 4: 5'-, & -3' homology checking, and 5: gene family checking to target into a real mRNA out of similar sequences. Fuzzy deducing checking protocol made it possible to select real VEGF mRNA from gene family in which there are many similar sequences.