Central segregation will inevitably occur in the continuous casting process, which will affect the homogeneity of steel. Serious central segregation will have a great impact on the structure, quality and performance of the steel. Therefore, accurate, rapid and convenient analysis of the element content distribution in steel will help guide metallurgists to quality control and process improvement. Original position statistic distribution analysis (OPA) is a quantitative statistic distribution technique of chemical composition and morphology in a large scale (cm²). It has been successfully used in the analysis of element segregation, porosity and inclusions in steel and super-alloy. In this paper, the element distribution of continuous casting round billet of 18CrNiMo7-6 low and middle alloy steel from the center to the edge was analyzed by original position statistic distribution analysis (OPA). The statistic conformity and statistic segregation of each sample at different positions were obtained. Meanwhile, each sample was analyzed 11 times by spark optical emission spectroscopy (OES)to obtain the relative standard deviation. The correlation of element distribution with statistic conformity, statistic segregation and the relative standard deviation was studied. The research showed that there was obvious segregation of P, Nb and S in each sample, and the statistic conformity was low. Their statistic segregation and relative standard deviation were high. The distribution of Cr, Ni, Mn, Mo and Si was relatively uniform, and the overall statistic conformity was high. Their statistic segregation and relative standard deviation were low. The sample of 6^# in the center of the round billet had the most obvious segregation, the lowest statistic conformity and the hightest statistic segregation and the relative standard deviation. The samples of 3^#, 7^# and 4^# near the center had obvious segregation, low statistic conformity, high statistic segregation and relative standard deviation. The samples of 9^# and 10^# at the edge of the round billet had minimal segregation, the highest statistic conformity, and the lowest statistic segregation and relative standard deviation. On the whole, each element distribution from the center to the edge was that the statistic conformity gradually increased, and the statistic segregation and the relative standard deviation gradually decreased. The results of statistic conformity, statistic segregation of OPA and that of the relative standard deviation of spark OES showed the same regularity in the element segregation of each sample. The trend of elemental content contours of each sample obtained from OPA also showed the same regularity with statistic conformity, statistic segregation and relative standard deviation. Therefore, the OPA technique can provide an accurate and rapid characterization of element distribution in materials, and provide a criterion method for material and process research to reflect the internal quality of materials.