A target discriminative probe (TD probe) having a modified dual specificity oligonucleotide (mDSO) structure represented by the following general formula I to allow for discrimination of a target nucleic acid sequence from a non-target nucleic acid sequence: 5'-X' p -Y' q -Z' r -3' wherein, X' p represents a 5'-second hybridization portion having a hybridizing nucleotide sequence complementary to the target nucleic acid sequence; Y' q represents a separation portion comprising at least three universal bases, Z' r represents a 3'-first hybridization portion having a hybridizing nucleotide sequence complementary to the target nucleic acid sequence; p, q and r represent the number of nucleotides; and X', Y' and Z' are deoxyribonucleotides or ribonucleotides; the T m of the 5'-second hybridization portion is lower than that of the 3'-first hybridization portion and the separation portion has the lowest T m in the three portions of X' p, Y' q and Z' r; the length of the 5'-second hybridization portion is 3-15 nucleotides, the length of the 3'-first hybridization portion is 15-60 nucleotides and the 3'-first hybridization portion is longer than the 5'-second hybridization portion; the TD probe has a single label or an interactive label system containing a plurality of labels to generate a detectable signal; the single label is a chemical single label, an enzymatic single label, a fluorescent single label, a luminescent single label, a chemiluminescent single label or a metal single label; the separation portion separates the 5'-second hybridization portion from the 3'-first hybridization portion in terms of hybridization events to the target nucleic acid sequence, whereby the hybridization specificity of the TD probe are determined dually by the 5'-second hybridization portion and the 3'-first hybridization portion such that the overall hybridization specificity of the TD probe is enhanced; wherein when the TD probe is hybridized with the target nucleic acid sequence, both of the 5'-second hybridization portion and the 3'-first hybridization portion are hybridized with the target nucleic acid sequence; wherein when the TD probe is hybridized with the non-target nucleic acid sequence, both of the 5'-second hybridization portion and the separation portion form a single strand, whereby the TD probe allows discriminating the target nucleic acid sequence from the non-target nucleic acid sequence; wherein the single label is positioned on the 5'-second hybridization portion of the TD probe, and the TD probe comprises a linker on its 3'-end for immobilization of the TD probe on the surface of a solid substrate; or wherein the interactive label system comprises a reporter molecule and a quencher molecule and (i) the reporter molecule and the quencher molecule all are positioned on the 5'-second hybridization portion; (ii) the reporter molecule and the quencher molecule each is positioned on each different portion of the 5'-second hybridization portion and the separation portion; or (iii) the reporter molecule and the quencher molecule each is positioned on each different portion of the 5'-second hybridization portion and the 3'-first hybridization portion.