Abstract: Objective To detect the expression of ERK1 and P16 in gastrointestinal stromal tumor group and normal control group and to discuss the correlation between them. Methods Tissue chip and immunohistochemistry named Elivison were used to respectively detect the expression of ERK1 and P16 in both 40 cases of gastrointestinal stromal tumor and 40 cases of normal control tissues and quantitative analysis of mean absorbent density of the expression of ERK1 and P16 was conducted respectively with the image analytic software: Image-Pro Plus (version 6.0) . Results The expressions of ERK was higher in GIST group than that in normal control group(P＜0.01), but the expression of P16 was lower（P＜0.01）. The expression of ERK1 and p16 were correlated with histological grade (P＜0.05) and not correlated with age, lump, histological type and recurrence .There was an inverse correlation between the activity of ERK1 and P16 in GIST（P＜0.05）. Conclusion In the tissue of GIST the expression of ERK1 was remarkable high and P16 was low.There was an inverse correlation between them.