DNA methylation of ID4 gene promoter occurred frequently in patients with acute leukemia and was found to be highly related to the tumor progression. Due to lack of the appropriate methylation detection methods, the relation between the quantification of ID4 methylation and the states of acute leukemia is still unclear. This study purposed to set up a methylation-specific quantitative PCR system for ID4 and investigate the specificity and sensitivity of this methylation detection. The plasmids combined with target gene as well as with internal reference were constructed, and the standard curves were set up by using above mentioned plasmids. The specificity of this detection system in cell lines was verified through techniques of MSP and quantitative MSP. The sensitivity of this detection system was verified by mixing methylation-positive and negative cell lines in varying proportions and through amplification of qualitative MSP. The results showed that the standard curves were establish successfully. The results of quantitative MS-PCR in cell lines were consistent with those of MS-PCR, and as low as 1: 10(-5) of ID4 methylation positive cells could be detected by the new methylation detection assay. In newly diagnosed acute leukemia patients, the positive rate of quantitative MSP was higher. It is concluded that a complete quantitative MSP system for ID4 methylation detection has been established and this quantitative MSP method has good specificity and high sensitivity.