Modularized polymerase chain reaction analysis instrument

The utility model discloses a modularized polymerase chain reaction analysis instrument. A photoelectric detection system of the existing quantitative polymerase chain reaction instrument needs at least two motors for realizing the line-by-line scanning in two directions. A test tube placing block of the modularized polymerase chain reaction analysis instrument is provided with a plurality of test tube placing holes in matrix A distribution; a scanning plate is arranged under the test tube placing block; the scanning plate is provided with a fluorescence excitation hole group and a fluorescence receiving hole group; the (n(i-1)+j)-th fluorescence excitation hole of the fluorescence excitation hole group and the (n(i-1)+j)-th fluorescence receiving holes of the fluorescence receiving hole group are respectively connected with the bottom of the (a)-th test tube installing hole of the matrix A through light guide bundles and matrixes; an excitation light source is positioned under the fluorescence excitation hole group, an optical filter arranged under the fluorescence excitation hole group is fixed with the top of the excitation light source; an optical filter arranged under the fluorescence receiving hole group is connected with a photoelectric converter, and a driving mechanism drives a case of a fluorescence detection component. The multi-line scanning is completed through the linear movement, and the stability and the reliability of a scanning movement mechanism can be improved.