Objective This study aimed to investigate the diagnostic efficacy of ultrasound measuring musculus biceps brachii in the diagnosis of protein energy wasting (PEW) in patients with hemodialysis (HD). Methods A retrospective collection of Chronic Kidney Disease (CKD) patients who received hemodialysis treatment in blood Purification Center, Department of Nephrology, Tianjin Third Central Hospital from January 2019 to September 2021 had been done. There were totally 83 patients, including 50 males and 33 females, aged 27-87(median age 63). The differences of biceps brachii ultrasound measurement data among different PEW groups had been compared and their diagnostic value of assessing PEW had been analyzed. Results BMI and longitudinal diastolic diameter of muscle biceps brachii showed certain diagnostic value for the state of protein energy wasting under the condition of different genders and normal protein intake (AUC>0.70). BMI lower than the cut-off value in men and women increased the risk of PEW, and the difference was statistically significant (OR=8.384, 95%CI 1.565-44.908, P<0.05); the longitudinal diastolic diameter of muscle biceps brachii lower than the cut-off value in men and women increased the risk of PEW, and the difference was statistically significant (OR=8.847, P<0.05). 95%CI 1.052-52.105, P<0.05). For patients with normal protein intake, the BMI lower than the cut-off value increased the risk of PEW, and the difference was statistically significant (OR=5.121, 95%CI 1.053-24.901, P<0.05); the longitudinal diastolic diameter of muscle biceps brachii lower than the cut-off value increased the risk of PEW, and the difference was statistically significant (OR=8.437, 95%CI 1.384-51.447, P<0.05). Conclusion The longitudinal diastolic diameter of muscle biceps brachii can be used as an auxiliary diagnostic criterion for the diagnosis of PEW. The state of the amyotrophy of the CKD patients with reduced BMI can be identified by the ultrasound measurement of longitudinal diastolic diameter of muscle biceps brachii, which could be a high-value diagnosis for protein energy wasting.