By using high-resolution laser grain size instrument Mastersizer 2000,the multimodal characteristics of grain size distribution of sediments from the Angulinao Lake(41°18'~41°24'N,114°20'~114°27'E),Santai River (41°18'N,114°24'E),Changjiang River(32°07'N,118°46'E),etc.are measured and carefully analyzed.The standard patterns and their grain size characteristics of various sediments are systemically summarized,the discrepancies of multimodal distribution among lake sediments are concluded and the physical me...