Precision of spreading powder is an important factor affecting selective laser melting forming quality. In order to achieve a better spreading powder effect, on the basis of researches on the existing equipment, basic constitution and working principles were introduced and structures of metal micropowder precise layer paving were designed such as lifting structure of platform, automatic lifting structure of scraper and scraper structure. The working principle of each structure was expounded. The metal micropowder precise layer paving device has the advantages of simple and compact and high automatic degree and will improve work efficiency and meet the requirements of selective laser melting rapid prototyping technology.