Under normal temperature and pressure, the quantitative analysis of magnesium and titanium elements in aluminum alloy is carried out by handheld laser-induced breakdown spectroscopy (LIBS) to verify the instrument's stability and reliability. The handheld LIBS has a built-in 1064 nm Nd:YAG pulsed laser with a reflective coaxial structure. The AvaSpec-Mini 2048 spectrometer with a measurement wavelength range of 240-420 nm is used in the experiment. The characteristic lines of magnesium element at 285.17 nm and 383.83 nm and those of titanium element at 323.45 nm and 334.94 nm are selected. Then the calibration curve model is established with the partial least square method. The slopes of calibration curves for the same element under different characteristic lines are close to each other, and the values of linear correlation coefficients R are all above 0.9893. Moreover, the measurement results have good consistency with the standard values, and the relative error is no more than 8.70%. The detection limits of magnesium and titanium elements in the samples can reach the level of 10 -4. The handheld LIBS can be used to realize the quantitative analysis of magnesium and titanium elements in aluminum alloys and thus that the handheld LIBS has certain stable and reliable performances is verified, which is of great significance to the development of a portable LIBS.