Objective The aim of this study was to explore the value of shear wave elastography in the diagnosis of nonalcoholic fatty liver in rats. Methods 52 male SD rats were randomly divided into control group (n=12) and experimental group (n=40). The experimental group was fed with methionine and choline deficiency diet for 1 week, 2 weeks, 3 weeks and 4 weeks to establish NAFLD models. At end of each experiment, the liver stiffness measurement (LSMa、LSMb) was measured by shear wave elastography under anesthesia and after execution. The standard deviation (SD) of the measurement results was calculated. The SWE of the liver was dissected to detect the liver stiffness measurement (LSMc)in vitro. Part of the liver was resected for pathological examination. The area under the receiver operating characteristic curve was used to evaluate the efficacy of SWE in diagnosing NAFLD under different conditions. Results Pathological examination showed that there were 17 rats in normal group and 35 rats in steatosis group. The standard deviation of liver hardness during anesthesia in normal group and steatosis group was[(1.70±0.56)kPa、(1.86±1.21)kPa], much higher than that SD in execution[(0.92±0.65) kPa、(1.08±0.73)kPa,P＜0.05],all much higher than that SD in vitro measurement [(0.26 ±0.16) kPa, (0.33 ±0.16) kPa, P<0.05].The LSMb and LSMc of steatosis group was[(3.95±1.78)kPa、(1.53±0.32)kPa],much higher than the LSMb and LSMc in normal group [(2.91±1.53)kPa、(1.23±0.16)kPa,P＜0.05].There was no significant difference in LSMa between steatosis group and normal group(P＞0.05).The areas under the ROC curve (AUC) by LSMb and LSMc in predicting Steatosis of liver were0.69 and 0.86, with the sensitivities and specificities of 60.0%、60.0% and 82.4%、100.0%. Conclusions The LSM of NAFLD rats is significantly higher than that of the normal group. After optimizing the instrument performance and measurement methods, SWE will have a good efficacy in the diagnosis of non-alcoholic fatty liver disease in rats.