NOVELTY - A cleaning and dispersing agent comprises 30-40 vol.% surfactant ingredient, 32-35 vol.% dispersing peat ingredient and 30-35 vol.% cleaning and washing ingredient. The surfactant ingredient contains 4-5C morpholine and/or N-methyl morpholine. The dispersed peat ingredient contains yeast fatty acid and calcium fatty amine. The cleaning and washing ingredient is in form of sulfurized calcium alkylphenates (T115B) and (T105) liquor obtained using fatty sulfurized alkylphenol calcium salt and sulfurized calcium alkylphenates (T115B) and (T105).    USE - Cleaning and dispersing agent used for bio-based methanol gasoline (claimed) for gasoline engine.    ADVANTAGE - The economical non-toxic environmentally-friendly agent having favorable cleaning and dispersing property is economically prepared by environmental-friendly method with reduced energy consumption and emission. The formation of carbon deposit is effectively prevented, formed carbon deposit is removed, fuel injection nozzle, air inlet valve and combustion chamber of gasoline engine are effectively prevented from emergence and production of carbon deposit, and removal ratio is 32.12-64.14% when using the gasoline containing the agent.    DETAILED DESCRIPTION - A cleaning and dispersing agent comprises 30-40 vol.% surfactant ingredient, 32-35 vol.% dispersing peat ingredient and 30-35 vol.% cleaning and washing ingredient. The surfactant ingredient contains 4-5C morpholine and/or N-methyl morpholine. The dispersed peat ingredient contains 10-20% yeast fatty acid and 15-20% calcium fatty amine. The yeast fatty acid is obtained from petroleum yeast fatty acid yeast extract of EAM-AC16 whose china general microbiological culture collection (CGMCC NO) accession number is 7429. The calcium fatty amine is in form of calcium alkyl salicylates (T154) and (T109) liquor prepared using polyisobutylene bissuccinimide and calcium alkyl salicylates in volume ratio of 1:1. The cleaning and washing ingredient is in form of sulfurized calcium alkylphenates (T115B) and (T105) liquor obtained using fatty sulfurized alkylphenol calcium salt and sulfurized calcium alkylphenates (T115B) and (T105) in volume ratio of 1:1. An INDEPENDENT CLAIM is included for preparation of cleaning and dispersing agent, which involves adding surfactant ingredient, dispersing peat ingredient and cleaning and washing ingredient into stirrer, and stirring uniformly at normal temperature under pH of 10.3-10.38.