Purpose: Type A acute aortic dissection (AAD) is an uncommon catastrophic cardiovascular disease with high pre-hospital mortality rate without timely and effectively treated. The aim of this study was to assess the value of serum platelet to hemoglobin (PHR) in predicting in-hospital mortality in type A AAD patients. Methods: A total of 183 type A AAD patients were included in this retrospective investigation from January 2017 to December 2019. Admission blood routine parameters were gathered and PHR was computed. The outcome was all-cause in-hospital mortality within 30 days. Results The average levels of serum PHR were significant higher in survivor group than those in non-survivor group (1.14 ± 0.57 vs 0.87 ± 0.47, p = 0.006) and serum PHR was an independent factor associated with in-hospital mortality (hazard ratio (HR): 2.831; 95% confidence interval (CI): 1.108–7.231; p = 0.030). ROC noted that 0.8723 was chosen as the ideal cutoff value with a sensitivity of 64.3% and specificity of 72.5%. In addition, the area under the ROC curve (AUC) was 0.693 (95% CI 0.599–0.787, p < 0.001). Conclusion: Admission serum PHR can be used as an independent predictor of in-hospital mortality in patients with type A AAD.