Objective: To assess the effect of high hepatic activity on the inferior myocardium in 99mTc-nitriles SPECT myocardial perfusion imaging. Methods :A heart and liver phantom was used. Images were performed in different heart-to-liver activity ratios(H/L) and heart-to-liver distances. The acquired projections were reconstructed with both contrast-enhancement(standard) and quantitative Ramp filters(Ramp-C and Ramp-Q). Considering the inferior-to-anterior (I/A) wall activity ratio in the no-liver phantom study reconstructed with Ramp-C as “normal”, the rate of decrease of I/A in other images was calculated. The relations between the rates of decrease of I/A and the various H/L and heart-to-liver distances were analyzed by linear correlation. Results: The decrease rate of I/A was linearly negatively correlated with the H/L(r=-0.986,P<0.01) and the heart-to-liver distances (r=-0.970,P<0.01).The I/A reconstructed with Ramp-Q were higher for 2.2%？10.0%than that with Ramp-C.Conclusion: High hepatic activity may create artifactual count loss in inferior wall in 99mTc-nitriles SPECT myocardial perfusion imaging.The degree of count loss is proportional to the activity level of a liver and inversely proportional to heart-to-liver distance.The extent of count loss, while tomographic images are reconstructed with Ramp-Q, is smaller than that with Ramp-C.