Background Initiation of dialysis encompasses new cardiovascular challenges on patients with end-stage renal disease (ESRD). This study used two-dimensional speckle-tracking echocardiography (2D-STE) to investigate the change of left ventricular (LV) myocardial function undergoing peritoneal dialysis (PD) within 1–3 months.Methods A total of 56 patients with ESRD and 27 healthy controls were enrolled in this prospective study. Mean duration of PD was 44.41 ± 16.44 days. We evaluated LV myocardial function of patients with ESRD in baseline and within 1–3 months after PD by 2D-STE with global longitudinal strains (GLS) and myocardial work (MW). Based on the level of serum phosphate before PD, patients were divided into two groups: the group with normal serum phosphate or hyperphosphatemia.Results Compared with healthy controls, patients with ESRD had impaired GLS (p .05) and no significant improvement was observed in GLS (p = .387). GLS of basal segments worsened in the hyperphosphatemia group (p = .005) and GWW reduced remarkably in the group with normal serum phosphate after PD treatment (p = .008). The change of left ventricular internal diameter in diastole (LVIDd) was the only parameter influenced GWI in post-dialysis patients (β = 0.324, p = .013).Conclusions Short-term PD treatment improved LV MW in ESRD patients. They benefited more when receiving treatment before the increase of serum phosphorus.