Objective To explore the value of three-dimensional spot tracking imaging (3D-STI) in evaluating bevacizumab in combination with chemotherapy in the treatment of subclinical cardiac injury caused by colorectal cancer.Method Fifty patients with advanced colorectal cancer treated with bevacizumab + FOLFOX anti-tumor therapy were selected as the observation group, and 50 healthy volunteers were selected as the control group. Echocardiography and 3D-STI techniques were performed before treatment, before the second cycle of treatment, before the 4th cycle, 1 day before the 6th cycle of treatment, and 3 months after the end of treatment. The left atrial anteroposterior diameter (LA), right atrial left and right diameter (RA), left ventricular end-diastolic inner diameter (LVEDs), end-systolic inner diameter (LVEDd), isovolemic diastolic time (IVRT), early and late mitral orifice diastolic peak flow rates (E and A), mitral valve E peak deceleration time (EDT), and early mitral annular diastolic peak velocity (e") were recorded in two-dimensional ultrasound mode. 3D-STI used EchoPAC 110 quantitative software to analyze left ventricular ejection fraction (LVEF), global longitudinal strain (GLS), longitudinal strain peak time dispersion (PSD), left ventricular myocardial overall work index (GWI), overall power rate (GWE), overall useful work (GCW), and overall no work ( GWW), the software automatically derives the strain bull"s eye diagram and the pressure-strain ring. Results Compared with the control group, LVEF decreased and E/e increased after 6 cycles of medication in the observation group (all P<0.05). Compared with the 6-cycle treatment group of the case group after 6 cycles and before medication, only the increase in the E/e treatment 6-cycle group was significant (all (all P<0.05). At the same time for 4 cycles, GLS, GWI and GWE decreased, P SD increased (all P<0.05), and 6 were used GLS, GCS, GWI and GWE decreased during the cycle , and P SD and GWW increased (all P<0.05). Compared with before medication, GLS, GWI and GWE decreased after 6 cycles, and P SD increased (all P<0.05) 。Conclusion After 6 cycles of bevacizumab combined with chemotherapy, both left ventricular systolic and diastolic function are affected, and diastolic function decline is more sensitive, which may also be earlier than systolic function impaired. At the same time, multiple parameters of pressure-strain ring can sensitively and effectively evaluate the left ventricular systolic function of patients with bevacizumab combined with chemotherapy, and provide a new objective quantitative index for the assessment of the severity of the patient"s condition.