The key factor to improve the sensitivity and accuracy of biosensing is to select suitable target recognition molecules.Currently,antibodies,aptamers,peptides and antibiotics are regarded as the most frequently used target recognition molecules.However,the molecules mentioned above have a certain limitations.For instance,antibodies and aptamers suffer from high production cost and difficulties for long-term storage,whereas peptides,antibiotics have a relatively low specificity towards the analyte.Therefore,it is necessary to find more superior substitutes.M13 phage is a type of flexible filamentous bacteriophage which could specifically infect E.coli with F factor.Due to its simple component and clear genetic background,M13 phage becomes one of the bacteriophages with earliest research history.M13 phage is the bacteriophage used by the 2018-Nobel Prize winner-George Smith to develop the phage display technology.By using phage display technology,the foreign peptide,protein or antibodies could be fused and coexpressed on the capsid protein surface of M13 phage,while by constructing phage display peptide library with phages that display various types of peptide and using biopanning technique,peptides with high specificity towards target analyte could be obtained.Up till now,thousands of highly specific peptides have been selected by biopanning from various phage display peptide libraries,and their affinities towards the target analytes are comparable to those of antibodies.Under this circumstance,M13 phage with targeting peptide has attracted the researchers’ interest in the field of analytical chemistry,and has become a novel platform for the construction of biosensing analysis.M13 phage consists of up to 2 700 copies of primary capsid protein pVIII wrapped in a helical form around the inner ssDNA and 3-5 copies of minor capsid proteins pVII,pIX,and pIII,pVI at both ends.This structure not only endows it good chemical stability,but also enables it to be functionalized by phage display technology or chemical modification.By coupling with appropriate signal output,M13 phages could be used for biosensing.In fact,M13 phages are an ideal platform to conduct signal simplification:by displaying/modifying the 3-5 copies of minor capsid proteins pIII with target recognition peptide and modifying the 2 700 copies of primary capsid protein pVIII with signal probes,one target-binding event can trigger a (3-5):2 700-fold signal amplification in theory.M13 phages with target recognition peptide on their pIII protein could be obtained by biopanning from phage display peptide library or by phage display techniques,whereas the signal probes reported so far include AuNPs,AgNPs,fluorescent dyes,SERS probes,etc.The detection methods coupled with M13 phages-based sensing platform include colorimetric method,fluorescent method,SPR detection,electrochemical sensing and quartz crystal microbalance method,etc.M13 phages could be applied not only for the sensing for microbes,metal ions,biomarkers and cells,but also used for the bioimaging of tumor cells and bacteria.Although great achievements have been obtained based on M13 phages,the M13 phages based biosensing still has some limitations,for example,due to the technique limitation,large proteins still cannot be displayed on the M13 phages surfaces,the mechanism for the interaction between target analyte and M13 phages needs further exploration.Nevertheless,the application prospect of M13 phages in the field of analytical chemistry is still promising.In this review,the structures of M13 phages,phage display technology and their application in the fields of optical sensing,electrochemical sensing,quartz crystal microbalance sensing and imaging analysis have been summarized.The development trend for the application of M13 phages in analysis is also prospected.