The invention provides a novel compound microbial fertilizer containing Pulullan and polyglutamic acid and a preparation method of the novel compound microbial fertilizer. The compound microbial fertilizer comprises a microbial fermentation inoculum, compound nutrients, Pulullan and polyglutamic acid, wherein the microbial fermentation inoculum is prepared by mixing fermentation liquors of bacillus megatherium, bacillus amyloliquefaciens, bacillus thuringiensis, bacillus mucilaginosus and azotobacter chroococcum according to the mass ratio of 1: 1: 1: 1: 1; the compound nutrients comprise nitrogen, phosphorus, potassium, trace elements, organic matters and compound amino acids. By applying the microbial fertilizer, the bud ratio, the plant height and the yield of highland barley can be obviously improved, and the highland barley is excellent in taste. Furthermore, the use level of irrigation water can be reduced by 10% due to the film-forming property of Pulullan and the water-retaining property of polyglutamic acid. In addition, Pulullan and polyglutamic acid are mixed to form a liquid mulch on the surface of soil, so that the use of a plastic thin film can be reduced, an environmental protective role can be played, the labor force is alleviated, and the cost is lowered by 10-20%.