漢初的法制事業，以蕭何作「律九章」最受世人注意，其他之韓信「申軍法」、張吾吾「定章程」、叔孫通「制禮儀」，少見有深論者。張蒼於秦時任拉下御史，明習天下圖書計籍;漢初又主計於相國府，近五年之久，對於上計事務之熟悉程度，當時無人可及。任計相與主計期間，總結以往之經驗，同時為順利推展業務，遂定章程以作為施行準則。章程之內容，應指上計之時程安排及其施行細則的相關規定。規劃上計之時程，涉及曆法的推算，而程本身又具有稽核之性質，張蒼的學術專長善於「算律曆」自秦時又任過柱下御史，對於上計事務相當熟悉，漢初以張蒼主任計相與主計，實為最佳之人選。

The legislations in the early Han Dynasty, the main research is all about Xiao He's "Lv Jiu Zhang", but the researches about Zhang Cang's "Ding zhang cheng", Han Xin' s "Shcn jun fa" and Shu Sun Tong's "Zhi li yi" are not many. Because of Zhang Cang served as the "zhu xia yu shi" in the Qin Dynasty, so he was familiar with the books and household registers Zhang Cang also served the post of "ji xiang" for five years in the prime minister palace in the early Han Dynasty, there is no one familiar with the books and household registers than him. In the period of the "ji xiang", Zhang Cang summarized his experiences and seeked smooth going the professional works to set into action, so he set up the "zhang cheng" There are two parts in the contents of "zhang cheng", the main function of “zhang" was to arrange the sequences for delivering the datas, "cheng" was for checking the books and household registers.