  We report precision measurement of aluminum atoms
${^{2}P_{1/2}}-{^{2}S_{1/2}}$ transition at 394 nm and
${^{2}P_{3/2}}-{^{2}S_{1/2}}$ transition at 396 nm in a hollow-cathode lamp
(HCL). Both absorption spectroscopy and saturated absorption spectroscopy (SAS)
are performed. From the absorption spectroscopy the Doppler linewidth is
estimated to be 2.6 GHz. The SAS spectroscopy is analyzed based on the
velocity-changing-effect model. With a frequency comb calibrated wavemeter, the
frequencies of ${^{2}P_{1/2}},{F=3}-{^{2}S_{1/2}},{F=2}$ transition and
${^{2}P_{3/2}},{F=4}-{^{2}S_{1/2}},{F=3}$ transition are measured to be
759.905401(10) THz and 756.547403(10) THz, respectively. The hyperfine
structure constants of aluminum atoms are determined and compared with
previously reported measurement results and theoretical calculation. Reasonable
agreement is found for the magnetic dipole constant (A constant), while the
electric quadrupole constant (B constant) has a large deviation.
