Objective To analyze the clinical manifestations and the relationship with genotype of 27 patients with Niemann’s disease type A/B diagnosed in the past 4 years at our hospital. Methods All patients, except one, were diagnosed with Niemann’s disease type A/B by measurement of acidic sphingomyelinase activity in peripheral blood. The peripheral blood DNA of the patients was isolated, and the exon and its adjacent intron sequences of SMPD1 gene were amplified by PCR to analyze the mutation of SMPD1 gene. Results Seven of the 27 patients had a positive family history. Eight patients (30%) had significant neurological symptoms within 1 year of age, consistent with classical type A. Four patients had significant neurological involvement after 2 years of age, consistent with intermediate type; the remaining 15 patients had no significant neurological symptoms and were classified as type B. One patient had secondary amenorrhea as the first symptom. Proteinuria was found in 2 patients with intermediate type and 1 patient with advanced type B, suggesting that the kidney is also a target organ for Niemann-Pick disease type A/B. Of the 27 patients, 2 pathogenic mutations were found in 24, only one pathogenic mutation was found in 2, and no mutation was found in 1, for a total of 23 different mutations, which did not include hotspot mutations in patients with other races of Niemann-Pick disease. Nineteen novel mutations were identified in these patients, including four small deletions/duplications in exons, one intron mutation, one termination mutation and 13 exon point mutations. Eight mutations occurred twice, with the highest incidence of 16.7%. By genotypic and phenotypic analysis, we identified 9 new mutations as severe mutations and 5 new mutations as mild mutations. 3 patients with intermediate phenotypes carried 1 severe mutation in the other allele in addition to a common shared mild mutation, suggesting that the intermediate phenotypes were in the intermediate state in terms of both clinical presentation and genotype. Conclusion The proportion of Chinese with Niemann-Pick disease type A is relatively high; the hotspot mutation of this gene in Chinese is completely different from other countries and has its own characteristics; attention should be paid to the enzymatic confirmation, genetic diagnosis and prenatal diagnosis of this disease to prevent the recurrence of this serious disease in the same family.