Objective To evaluate the prognostic value of several indexes of laboratory and ultrasonic cardiogram for adverse events in 3 months following the diagnosis of acute non-high-risk pulmonary embolism. Methods A total of 266 cases of acute non-high-risk pulmonary embolism patients diagnosed and treated in Beijing Anzhen Hospital during 2016 to 2017 were retrospectively analyzed. The patients were divided into a bad event group and a control group according to whether there was a bad event happened in 3 months following the diagnosis. The general data, indexes of laboratory and ultrasonic cardiogram were compared. Univariate and multivariate COX regression analysis were conducted to explore independent risk factors for 3 months’ poor prognosis. Results The bad outcome group had a significantly higher value of the proportion of suffering from connective disease and active cancer, C-reaction protein, monocyte/lymphocyte ratio (MLR) and urea while a significantly lower level of red blood cell count and hemoglobin compared with the control group (all P<0.05). Univariate and multivariate COX regression analysis showed that both the MLR (hazard ratio 14.59, 95% confidence interval 1.48 - 143.69, P=0.02) and suffering from connective disease (hazard ratio 5.85, 95% confidence interval 1.11 - 30.81, P=0.04) remain significantly different between the bad events group and the control group. Conclusion MLR at the admission may be related to the 3 months death of acute non-high-risk pulmonary embolism.