Cytarabine is an effective drug for the treatment of leukemia. In this paper, the dissolution behavior of Cytarabine in normal saline and citric acid solution was studied using microcalorimetry in order to obtain integral and differential heat of solution. This study not only established the relation between the solute and heat, but also determined the kinetic equations of Cytarabine in normal saline and citric acid solution as well as the half-life, ΔsolHm, ΔsolGm and ΔsolSm. This work could provide experimental support for the clinical study of Cytarabine.