Objective: To observe the etiology, comorbidities, clinical features and treatment patterns of hospitalized patients with heart failure (HF) in China. Methods: Data were collected prospectively on hospitalized patients with HF who were enrolled in China Heart Failure Center Registry Study from 169 participating hospitals from January 2017 to August 2018. In this cross-sectional study, patients were stratified by left ventricular ejection fraction (LVEF) category: heart failure with reduced ejection fraction (HFrEF, LVEF<40%); heart failure with mid-ranged ejection fraction (HFmrEF, 40%≤LVEF<50%) and heart failure with preserved ejection fraction (HFpEF, LVEF≥50%). The clinical data were collected, including demographic information, diagnosis, signs, electrocardiogram, echocardiography, laboratory tests, and treatment. Results: A total of 31 356 hospitalized patients with HF were included, 19 072 (60.8%) were males and the average age was (67.9±13.6) years old. The common causes of HF were hypertension (57.2%), coronary heart disease (54.6%), dilated cardiomyopathy (14.7%), valvular heart disease (9.2%). The common complications were atrial fibrillation/atrial flutter (34.1%), diabetes (29.2%), and anemia (26.7%). 32.8% of patients had a history of hospitalization for HF within the previous 12 months. There were 11 034 (35.2%) patients with HFrEF, 6 825 (21.8%) patients with HFmrEF and 13 497 (43.0%) patients with HFpEF. Compared with patients with HFpEF, patients with HFrEF had a lower systolic blood pressure ((124.7±21.1)mmHg(1 mmHg=0.133 kPa) vs. (134.9±22.9)mmHg), faster heart rate ((85±19) beats/minutes vs. (81±19)beats/minutes), and higher percentage of New York Heart Association (NYHA) class Ⅳ, smoking, alcohol, left bundle branch block, and QRS time≥130 ms, and higher levels of blood uric acid, BNP, and NT-proBNP (all P<0.05). Compared with patients with HFmrEF and HFrEF, patients with HFpEF were older, more women, and higher comorbidity burden including hypertension, atrial fibrillation/atrial flutter, anemia and chronic obstructive pulmonary disease (all P<0.05). HFmrEF took a mid-position between HFrEF and HFpEF in age, gender, heart rate, systolic blood pressure, hypertension, atrial fibrillation/atrial flutter, anemia, and chronic obstructive pulmonary disease (all P<0.05). Patients with HFmrEF had the highest proportion of coronary heart disease, myocardial infarction and percutaneous coronary intervention (all P<0.05). During hospitalization, loop diuretics were used in 90.2% of patients, and intravenous inotropics were used in 20.4% of patients. The use of ACEI/ARB/ARNI, β blockers and aldosterone receptor antagonists at discharge were 71.8%, 79.1% and 83.6% in HFrEF and 69.9%, 75.5% and 72.4% in HFmrEF, respectively. The use of digoxin at discharge was 25.3% (HFrEF 36.7%, HFmrEF 23.1%, HFpEF 17.0%). The rates of cardiac resynchronization therapy and implantable cardioverter defibrillator in HFrEF were 2.7% and 2.1%. Conclusions: Among the hospitalized patients with HF in China, coronary heart disease and hypertension are the mostly prevalent causes. HFpEF accounts for a large proportion of hospitalized patients with HF. HFrEF, HFmrEF and HFpEF have different etiology and clinical features. In real-world, there are still large gaps in the effective application of the guideline recommended therapies to HF patients, especially the non-pharmacological therapy option, which needs to be improved further in China.