Objective To investigate the effect of miR-25-3p targeting a disintegrin and metalloproteinase 10 (ADAM10) on the differentiation of P19 cells into cardiomyocytes by regulating Notch signaling pathway. Methods P19 cells were induced to differentiate into cardiomyocytes with dimethyl sulfoxide (DMSO) and collected at 0, 5, and 10 days. The mRNA levels of myocardial differentiation markers GATA4, cTnT, atrial natriuretic polypeptide (ANP) and the level of miR-25-3p were detected by real-time quantitative PCR (qRT-PCR). The protein level of ADAM10 was assessed by Western blot analysis. The miR-25-3p was over-expressed in P19 cells by infected with retrovirus, and the expression levels of miR-25-3p and ADAM10 in the infected P19 cells were detected by qRT-PCR and Western blotting. Bioinformatics were used to predict the targeted matching relationship between miR-25-3p and ADAM10 gene, which was then verified by the luciferase reporter gene system. After infection, P19 cells were induced to differentiate by DMSO for 10 days. Then the protein expression of cTnI was detected by immunofluorescence assay to calculate the differentiation rate of cardiomyocytes, and the proteins expression of myocardial differentiation markers GATA4, cTnT, ANP and Notch signaling pathway-related molecules Notch1, hes family bHLH transcription factor 1 (Hes1), Hey1, and Hey2 were detected by Western blotting. Results During the 0, 5 and 10 days of the differentiation of P19 cells into myocardial cells, the mRNA expression levels of GATA4, cTnT, ANP and the protein expression level of ADAM10 gradually increased, while the expression level of miR-25-3p gradually decreased. After retrovirus infection, the expression level of miR-25-3p in the infected P19 cells went up significantly, while the protein expression level of ADAM10 went down significantly. Subsequently, ADAM10 was confirmed as a target gene of miR-25-3p. After the 10 days of differentiation, over-expression of miR-25-3p significantly decreased the differentiation rate of cardiomyocytes, and down-regulated the levels of the markers of myocardial differentiation-related proteins GATA4, cTnT, ANP, and the Notch signaling pathway related-proteins, including Notch1, Hes1, Hey1 and Hey2. Conclusion The miR-25-3p can significantly inhibit the differentiation of P19 cells into cardiomyocytes, and the mechanism may be related to inhibite the activation of Notch signaling pathway by depressing ADAM10 expression.