Objective Compare and analyze the value of β-hydroxybutyrate from two kinds of blood ketone instruments (Optium Xceed blood ketone body instrument from American Abbott laboratories and TBS-1 blood ketone body instrument from Beijing Yicheng company), and provide instructions for clinical applications. Methods Select 7 children patients with epilepsy which have a response to ketogenic diet. The two kinds of blood ketone instruments were used to test blood ketone value of whole blood synchronously in five different periods, and compare the 70 results. Results The measuring results obtained from these two kinds of blood ketone body instruments have statistical difference significantly. The value acquired from TBS-1 blood ketone body instrument is lower than that from Optium Xceed blood ketone body instrument. Measurements using a paired t test, the value of t=12.14, P<0.01. The results from two kinds of blood ketone body instruments are statistically significant. Conclusion The values from 2 kinds of blood ketone instruments are different, which would influence the clinical judgment. At present, the key problem is that there is lack of special blood ketone measure technology for patients with ketogenic diet. How to improve the measure accuracy of high-level blood ketone value remains the future work.