Objective: To explore the value of ultrasonic left ventricular pressure-strain loop (PSL) for evaluating left ventricular myocardial work in patients with hypothyroidism. Methods: A total of 42 patients with hypothyroidism treated in Sichuan Provincial People's Hospital were included as the hypothyroidism group , and 44 healthy volunteers were also employed as the control group. Collect two-dimensional ultrasonic data and use the left ventricular PSL technology to obtain the myocardial global longitudinal strain (GLS) , global work index (GWI), global constructive work (GCW), global wasted work (GWW) and global work efficiency (GWE) , and manually calculate the average values of myocardial work index (MWI) , myocardial work efficiency (MWE), constructive work (CW), and wasted work (WW) of basal, middle and apical segments of myocardium. The differences in relevant parameters between the two groups were compared. Results: ①Routine echocardiographic parameters: compared with the control group , interventricular septal thickness at end-diastole (IVSd) and left ventricular posterior wall thickness at end-diastole (LVPWd) were larger, and early diastolic E peak blood flow (E)、late diastolic A peak blood flow (A) at mitral valve orifice、early diastolic mitral annular peak velocity(e') of left ventricular lateral wall and E/A were lower in the hypothyroidism group (all P < 0.05).②Left ventricular global myocardial work parameters: compared with the control group, GWW was higher and GLS , GWI , GCW and GWE were lower in the hypothyroidism group (all P < 0.05).③Myocardial work parameters of each segment of left ventricle: compared with the control group , MWI , CW and MWE of basal segment , middle segment and apical segment in the hypothyroidism group were lower , while WW were larger (all P<0.05). Conclusion: PSL technique could be used to quantitatively assess myocardial work in patients with hypothyroidism for providing accurate imaging evidences for the early diagnosis and efficiency evaluation of hypothyroidism patients treatment .