Objective To analyze the characteristics of contrast-enhanced ultrasound (CEUS) of primary small hepatic carcinoma (PSHC) with different differentiated degrees so as to investigate the clinical effectiveness of application of CEUS in diagnosis and classification of this disease. Methods A retrospective analysis of CEUS data of 47 patients with PSHC confirmed by surgery and pathology was made. Quantitative parameter of CEUS for PSHC with different differentiated degrees was compared. Enhanced intensity among differentiated degree groups was compared in arterial phase, portal phase and delayed phase. Compared to pathological examinations, the diagnosis accordance rate of CEUS was analyzed. Results According to the postoperative pathological results of 47 patients, 22 cases were well differentiated, 20 cases were moderately differentiated and 5 cases were poorly differentiated. Both the arrival time and peak time were similar in PSHC with different degrees of differentiation, without statistically significant difference (P>0.05), but with statistically significant difference compared with the time to contrast washout (P<0.05). There was significant difference of enhanced intensity among differentiated degree groups in the portal phase and delayed phase (P<0.05). As the differentiated degree grew, the proportion of low enhanced intensity increased. 43 patients with PSHC were correctly diagnosed by CEUS, with a pathological diagnostic accordance rate of 91.49%. Conclusion Certain differences were seen between the CEUS characteristics of PSHC with different differentiated degrees . CEUS provided important references for clinical diagnosis and classification of PSHC.