Abstract: The present invention relates to a probe for detecting Mycobacterium tuberculosis complex (MTBC) and Mycobacterium tuberculosis (MTB) from clinical specimens. The method mainly comprised two steps: (1) amplifying a target DNA of the clinical specimens through nested PCR; and (2) hybridizing to the target DNA with a gold nanoparticle probe. The presence of MTB or MTBC was detected after the absorbance at 525 nm was determined with a spectrophotometer during hybridization at a defined time. Direct observation on color changes can also be detected after a longer incubating time. The merits of this assay include being easy to operate, sophisticated detection equipment is not necessary, low cost, time saving, and, high sensitivity and specificity.