Fruit and vegetables diseases are always caused by pathogenic microorganisms and traditionally, chemical control such as fungicide treatment was widely applied, which helped to cause chemical residues, environmental pollution and resistance in fungi, etc. Alternatively, microbial biocontrol methods were favored due to their safety, effectiveness and environmental harmlessness. In this paper, we reviewed the update investigations about the biocontrol effect and involved mechanisms of Pseudomonas fluorescens, one kind of biocontrol bacteria and plant growth-promoting rhizobacteria. We provided the basic information of P. fluorescens on biological control and discussed related mechanisms including parasitism, competition for nutrients and space sites, production of secondary resistance metabolites and initiation of systemic resistance, responsible for the biocontrol effect. Also, we illustrated the current research result for the improvement of biocontrol efficacy, such as inoculant mixing, physical methods, chemical treatments and molecular technologies.