Abstract: AIM:To observe the expression of tumor necrosis factor-alpha ( TNF- α) and its receptor I ( P55 ) in different pterygium and discuss the role of TNF-α and receptor I (P55) in pterygium. <br> METHODS: Immunohistochemistical staining method ( PV) was adopted to detect the expression of TNF-α and receptor I in pterygium ( 72 eyes ) and para-pterygium conjunctival tissue ( 30 eyes ) . The relationship between the expression and clinical-pathological parameters was also analyzed. <br> RESULTS:The positive rates of TNF-αwere 65. 3% (47/72), 26. 7% (8/30) in pterygium and para-pterygium conjunctival tissue. The positive expression of TNF-α had statistic difference between the two groups (χ2=12. 706, P<0. 01). The positive rates of TNF-α receptor I were 56. 9% (41/72), 16. 7% (5/30) in pterygium and para-pterygium conjunctival tissue. The positive expression of P55 had statistic difference between the two groups (χ2=13. 875, P<0. 01). The positive rate of TNF-αin recurrent pterygium group was higher than primary pterygium group (χ2=6. 547, P=0. 011). There had no statistically significance of the expression intensity between the two groups (F=1. 288, P=0. 393); the positive rate in advanced pterygium group was higher than quiescent pterygium group (χ2=4. 082, P=0. 043). The expression intensity had no statistically significance between the two groups (F=0. 489, P=0. 708). The positive rate of P55 in recurrent pterygium group was higher than primary pterygium group (χ2 =9. 907, P= 0. 002). There had no statistically significance of the two group's expression intensity ( F = 1. 175, P = 0. 424 ); the positive rate in advanced pterygium group was higher than in quiescent pterygium group (χ2=11. 140, P=0. 001). The expression intensity had no statistically significance between the two groups (F=0. 665, P=0. 621). <br> CONCLUSION:The expression of TNF-α and P55 are changing according to the development of clinical staging and onset. The expression of TNF-α and P55 may be related to clinical classification, staging and patient's working conditions of pterygium. There has no significant difference expression intensity of TNF - α and P55 in clinical staging and onset of pterygium.