A method for detecting the presence of a variation or the type of a variation in a target nucleic acid, comprising: preparing a probe directed to the nucleic acid target(s) where the detection of nucleic acid sequence variation is needed; wherein the probe is a self-quenched nucleic acid probe, wherein the probe is labeled at opposite ends with a fluorescent group and a quenching group in such a way that fluorescence or fluorescence intensity increases when the probe hybridizes with the target nucleic acid sequence compared to fluorescence or fluorescence intensity in the absence of the target nucleic acid sequence, wherein: if the 5' end of the probe is labeled with the fluorescent group, then the 3' end of the probe is labeled with the quenching group; or if the 3' end of the probe is labeled with the fluorescent group, then the 5' end is labeled with the quenching group, and said probe does not comprise a modification that is able to resist the exonuclease activity of a polymerase, and said probe is a linear probe, amplifying a fragment (or fragments) comprising the nucleic acid(s) to be tested using asymmetric PCR, wherein one PCR amplification primer in the reaction mixture is relatively in excess and the strand produced with the elongation of said primer hybridizes with the probe and the polymerase used in the asymmetric PCR has an exonuclease activity, and adding said probe into the amplification reaction before the amplification; after the amplification, performing melting curve analysis for the amplification product comprising said probe added in step; determining whether the nucleic acid(s) to be tested has a variation and optionally the possible type of variation, based on the corresponding melting temperature detected by the self-quenched probe (or the melting temperature of the hybrid formed between said probe and the nucleic acid sequence to be tested), or differences of said melting temperature. preparing a probe directed to the nucleic acid target(s) where the detection of nucleic acid sequence variation is needed; wherein the probe is a self-quenched nucleic acid probe, wherein the probe is labeled at opposite ends with a fluorescent group and a quenching group in such a way that fluorescence or fluorescence intensity increases when the probe hybridizes with the target nucleic acid sequence compared to fluorescence or fluorescence intensity in the absence of the target nucleic acid sequence, wherein: if the 5' end of the probe is labeled with the fluorescent group, then the 3' end of the probe is labeled with the quenching group; or if the 3' end of the probe is labeled with the fluorescent group, then the 5' end is labeled with the quenching group, and said probe does not comprise a modification that is able to resist the exonuclease activity of a polymerase, and said probe is a linear probe, amplifying a fragment (or fragments) comprising the nucleic acid(s) to be tested using asymmetric PCR, wherein one PCR amplification primer in the reaction mixture is relatively in excess and the strand produced with the elongation of said primer hybridizes with the probe and the polymerase used in the asymmetric PCR has an exonuclease activity, and adding said probe into the amplification reaction before the amplification; after the amplification, performing melting curve analysis for the amplification product comprising said probe added in step; determining whether the nucleic acid(s) to be tested has a variation and optionally the possible type of variation, based on the corresponding melting temperature detected by the self-quenched probe (or the melting temperature of the hybrid formed between said probe and the nucleic acid sequence to be tested), or differences of said melting temperature.