Since the time our country carried out the new government purchasing system, greater progress has been made in ensuring the quality of the purchased materials and the reasonable use of the government purchasing funds and so on, with the restriction of the Law of Government Purchasing. But in practical operations, some unharmonious voices are produced. It's apparent that every government of the world is faced with government purchasing problems. Though their purchasing systems are different, the perfect supervisory systems are indispensable. The paper tries to discuss the practical defects in the existing Law of Government Purchasing of our country to construct the supervisory model containing the supervisory body both inside and outside, which includes the following links: the check of the purchasing items, the check of bids and tenders, timely supervision of the tender winners and feedbacks and adjustments, and involves such supervision of government purchase items: kinds, varieties, specifications, quality index and price index and so on. Therefore an effective control network is constructed in order to ensure the accomplishment of the government purchasing.