Abstract: In order to solve problem of how to determine scraper pitch when en-masse conveyors transported different materials， MS and MC en-masse conveyors were taken as the research object, the influence law of the scraper area, conveying material, machine slot height and width on the scraper pitch were analyzed. The analysis results show that the different conveying materials have a great influence on the scraper pitch. For MS en-masse conveyor, the scraper pitch increases with increasing of the scraper area and decreases with increasing of slot width and height when other factors remain unchanged. Because the internal friction angles of different material are different, scraper pitch decreases first and then increases, at about 25° to the minimum. For the MC en-masse conveyor, scraper pitch decreases as the scraper width increases, and increases as the scraper height increases. When the internal friction angle is about 30°, the minimum value of scraper pitch is obtained.