Objective To observe the incidence of fragmented QRS complex (fQRS)and ST Segment depression fQRS (STD fQRS)during the first 48 hours after non-ST elevation myocardial infarction(NSTE MI)and discuss the value of predicting mortality in patients with NSTE MI .Methods Based on the ECGs ,the patients with NSTE MI were divided into two groups :fQRS and non fQRS group .And then fQRS group was divided into two sub-groups :STD fQRS and non-STD fQRS group .Their mortality was studied during long-term follow-up .Results (1)731 patients with NSTE ACS [the NSTE MI group(n=609) and the UA group(n=122)] were studied .The incidence of fQRS in the NSTE MI group was higher than that of the UA group .(2)All cause mortality in the fQRS group were higher than that in the non-fQRS group ,and all-cause mortality in the STD fQRS group were higher than that in the non-STD fQRS group ,all the above results were not only in the early stages of NSTE MI ,but also in the long term fol-low-up .(3) Multivariate Cox regression analysis revealed that STD fQRS was an independent significant predictor for all cause mortality ,but not of the fQRS .Conclusion The STD fQRS may be an independent predictor of mortality in patients with NSTE MI .