Disclosed are a crystalline free acid of a NEP inhibitor, a calcium salt polymorph of same, a preparation method for same, and applications thereof. The present invention relates to a crystalline free acid of the NEP inhibitor compound (also known as HAS-000129) as represented by formula 1, a calcium salt polymorph of same, a preparation method for same, and applications thereof. The powder x-ray diffraction pattern of the HAS-000129 crystalline free acid comprises peaks located at diffraction angles (2θ) 6.4±0.2°, 15.9±0.2°, 20.8±0.2°, and 19.0±0.2°. The present invention also relates to a pharmaceutical composition containing an efficacious dose of the HAS-000129 crystalline free acid and the calcium salt polymorph and uses of the composition in preparing medicaments for treatment or prevention of neutral endopeptidase-related diseases, cardiovascular diseases, hypertension, acute and chronic heart failure, left ventricular dysfunction, hypertrophic cardiomyopathy, diabetic cardiomyopathy, supraventricular and ventricular arrhythmias, atrial fibrillation, atrial flutter or detrimental vascular remodeling. The HAS-000129 process of the present invention has great operability, physical and chemical stability, and facilitated preservation and pharmaceutical application.