Objective:To investigate myocardial transcription factor GATA4 and myocardial specific marker cardiac tropenin T (cTnT) expression of P19 cells differentiated into cardiomyocytes in diabetes-like environment. Methods:P19 cells were induced to myocardial cells in supplemented diabetic teratogenic medium. Real-time PCR and Western blot were performed to detect GATA4 and cTnT expressions in the two groups on differentiated process. Results:Compared with the control group,the elementary bodies(EB) that cultured in diabetes-like environment propagated obviously slower and the aggregation outgrowths were scattering and sparse. The volumes of GATA4 in diabetes-like environment medium on day 6,8 and 10 (0.05 ± 0.06,0.11 ± 0.04 and 0.45 ± 0.12) of culture were significantly lower than the same time of the control group(1.00 ± 0.04,0.44 ± 0.06 and 0.78 ± 0.20) of culture respectively. The volumes of cTnT in diabetes-like environment medium on day 6,8 and 10 (0.12 ± 0.03,0.07 ± 0.04 and 0.46 ± 0.11) of culture were significantly lower than the same time of the control group (1.02 ± 0.25,0.25 ± 0.02 and 0.71 ± 0.21) of culture respectively. Western blot assay resulted with the integral optical density (IOD) values of quantitative data. The protein expressions of GATA4 in diabetes-like environment medium on day 6,8 and 10 (0.40 ± 0.06,0.25 ± 0.03 and 0.92 ± 0.13) of culture were significantly lower than the same time of the control group (0.69 ± 0.09,0.75 ± 0.08 and 1.05 ± 0.07). The protein expressions of cTnT in diabetes-like environment medium on day 6 and 8(0.39 ± 0.08,0.37 ± 0.05) of culture were significantly lower than the same time of the control group (0.79 ± 0.05,0.54 ± 0.07). There were significant differences between the day 6 and 8 groups(P < 0.05). Conclusion:P19 cell induced decreasingly to myocardial cell differentiation in diabetes-like environment culture.