The invention provides a signal amplification and signal reporting integrated oligonucleotide probe. The probe is a pair of DNA hairpin sequences designed on the basis of a target molecule and having cohesive ends, substantially is a product combining a hybridization chain reaction fuel molecule with a G-quadruplex sequence, has the characteristic of target molecule signal cascade amplification of the hybridization chain reaction in an enzyme-free isothermal manner, and enables the amplified target molecule signal to be conveniently and simply detected through the introduction of a signal reporting element G-quadruplex sequence. The invention also provides a method of an enzyme-free isothermal nucleic acid probe mediated by the above probe. The method enables the signal of an object to be detected to be amplified and detected under a normal temperature condition without any enzymes, and has the advantages of sensitivity, accuracy, simplicity, and easy implementation.