Abstract: Objective 　To investigate the value of immuocytochemist ry of cell blocks in find the primary ori2 gin of the metastatic adenocarcinoma. Methods 　A totalof 150 samples were examined using immunohis2 tochemist ry with TTF21, CA125, CDX2, Villin and GCDFP215. 30 cases of lung adenocarcinoma, 30 ca2 ses of ovarian adenocarcinoma, 30 cases of bowel adenocarcinoma, 30 cases of gast ric adenocarcinoma, and 30 cases of breast adenocarcinoma. All the specimens obtained by lymph nodes fine2needle aspiration biop sy, confirmed with the postoperative pathohistology. Results 　Positive express of TTF21 were 90 % in lung adenocarcinoma, those of CA125 were 90 % in ovarian adenocarcinoma, those of CDX2 were 93 % and 50 %, and vilin were 76 % and 63 % in bowel adenocarcinoma and gast ric adenocarcinoma respective2 ly. Those of GCDFP215 were 86 % in breast adenocarcinoma. Conclusion 　Associated with FNAB cell blocks were t reated with plasmase and immuocytochemist ry not only can diagnose the lesions and confirm the histological types, but also can find minimally invasive carcinoma and confirm the primary origin, it's help to make rational therapy and prognosis, especially those of patient s who only have a lymph node lumps than any another clinical symptom.